What perks do you even use on nemesis?

In my opinion Nemesis has probably one of the slowest ramp up times(outside of trap based killers) in the game and really suffers from time inefficiency in the early-mid in regards to infection and his 8 free health states. Especially if survivors are smart and get infected by zombies at the start to deny fast T2. I think any perks that help early game are massive on him as a result (corrupt/lethal), also anything that can help reduce those early/mid chase times as well (STBFL), for regression I use the standard pop, and I also like to use sloppy to help slow down the game in regards to healing and it also combos well with STBFL.

You can also do a fun meme build with undetectable as his initial tentacle strike on uninfected survivors does not deal any damage thus does not deactivate trail of torment, ToT + undetectable addon when killing a zombie + ribbon adddon for faster zombie respawn time + tinkerer + whatever you want is a fun build that has a lot of control over when you go undetectable but I think it is really inferior in terms of winning compared to the build I usually use. That said it is immensely satisfying sneaking around.

In regards to your perks you listed out above I don't think thanat is good on him due to him having no map mobility nor any downside to healing. Plague and Legion are the kings of thanat and you need something on that level to make really good use of it imo. Hysteria is very meh, the oblivious effect can be massive but you don't really know how much value you are getting out of it in any given game.

My only advice is to remember your zombies as a baked in gen reduction you almost dont need ruin because of them

I usually use Nurses, Starstruck, Devour and Ruin and I try to look for the healing silhouettes when choosing where to hook someone.

If the totems go down, the two perks I have left are usually enough but if the totems stay up then I get to have a little fun.

I currently use BBQ,Corrupt Intervention,Lethal Persuer and STBFL on him.

Corrupt + Lethal helps me to get that first chase starting as soon as possible to get snowball going on.

BBQ is nice for points and a little bit of tracking,while STBFL is a REALLY good chase perk that also helps me to punish very altruistic/aggressive survivor playstyles

Stbfl is honestly incredibly good on him. if you get a few hits on non obsessions, and just always use your tentacle on the obsession similar to a pig, demo, huntress or hillbilly, you can get max stacks and keep them easily. and if someone goes for a hook save infront of you it becomes complete denial. Also its fun to punch someone and instantly grab them, or punch them again, or punch into a tentacle whip combo, which practically instantly downs them.

BBQ in general for locating and extra bp - swap out for whispers or nurses if you don't wish to use it

Pop for gen delay, eruption paired with it. Or just pop in general

pallet destroyer with enduring spiritfury, they can't loop pallets with it and you can completely ignore them after you get to tier 2.

Even just popping on spirit fury allows you to ignore pallets, walk through after their destroyed and hit them with a tentacle whip as the distance gained after a pallet is destroyed automatically is minimal.

Bamboozle allows you to force out pallets easier if used smartly, and can make loops beyond hellish when you can pretty much auto break pallets

If your only focusing on m2's with his tentacle for the most part (since they auto break pallets in t2, and have longer reach) coup de grace, can be incredibly and unironically clutch because no one will ever expect it, and you can save stacks very easily.

ultimate gen delay being pop, opression, eruption. Pair all three together and when you start kicking gens early game, it tells you where people might be. go there, down someone, then by then you likely have opression back up, You kick a gen after the down to get pop, eruption on the first gen, and opression on other gens which is incredibly debilitating if you can get some early pressure, keeping it up. put on brutal as well, for some early chase pressure if people are pre throwing pallets to prevent you getting t2, and also to break gens faster and in chase without losing too much distance.

pwyf nemesis, paired together is pretty funny early game. get hit by a pallet as you tentacle strike, they sprint off and you instantly lose chase temporarily gaining one token, and then catch up and strike them again faster. Maybe pair this with enduring spirit fury for the ultimate don't stun me or your cucked build.

Anything with undetectable is pretty clutch, whether its trial of torment, or tinkerer, he's a pretty quiet killer despite his height and bootstomps. Monitor and abuse is pretty decent for this reason alone, allowing you to get closer before they run away.

The Build I use and am comfortable with:

BBQ-->Just for stonks to be honest. But it is also nice to see Survivors if you are not at Tier 3 already.

Corrupt Intervention-->Best Slowdown-Perk.

Lethal Pursuer-->To get into the game as fast as possible, yes, you will only have 3 Perks after 9 seconds, however, getting into a chase ASAP (and getting the Mutation Rate growing ASAP) is important.

Infectious Fright-->Nemesis shreds through Pallets pretty quickly, so I just run Infectious Fright because the possibility is quite high that I already got rid of most Pallets in one area, so it might be an easy chase to get the Survivors I see with IF.

STBFL is also decent on him, however, I did not use it anymore, because I felt forced to use my M1, when I wanted to go for the M2 instead, just to rank up Stacks. But a strong Perk on him.