Okay I don't think anything works for all kids, so I will say that as a disclaimer upfront. I can offer things you can consider though & see if they fit your family or might work for this child.
Baths can be invigorating. All people experience them differently. For some people it's just what is called for at the end of a long day before curling into bed, for others it's a way to get a second wind. If you are doing a nightly bath, I would experiment with doing it as early as possible instead, so perhaps when you just get home & while one gets dinner around, the other bathes him.
At this age his total daily sleep requirements will drop a little. At this age most kids are needing about 11-12hrs total per day. You make no mention of naps in here. If he is still napping you can start too with trying to eliminate that. Many people will claim all kids this age need a nap & I just do not accept that. Every kid is different. I have 3. Two did nap at this age. The other dropped his napping at 18 months. IF he got a nap all night was an absolute misery of broken sleep, going to bed too late, waking too early. If we did no naps he slept a solid 12-14hrs peacefully. If someone watched him & "knew better" and let him nap, I'd be in misery for a week trying to get him sorted back to a good routine. So if you haven't tried a day without napping, try it. It is true that most this age still need an nap. It is not true that all do.
Another thing I have noticed in my own is that I can see an increase in activity right when they should go to bed. So I make sure they are ready well ahead of time & then let them go about & play. I do not do a real serious book, song, blah blah. I do all that earlier, then free play. If I watch, I think a child that fights sleep will have a tell tale increase in activity in an attempt to keep themselves up. If I take them right then & just shush, pat & tuck them right in, I can normally have them down in less than 10 mins at this age. If I miss that window, heaven help me.
I have found that doing yoga with them in evenings is good too. There are actual yoga videos meant for toddlers so you can do it with them. My older son used to say "Wet's do Dawoga" (meaning let's do the yoga). It is something all little ones I have watched like doing as I use it when everyone is getting too wound up on rainy days indoors (I watch other children intermittently). They do a lot of being silly, but that is fine. It's about trying to slow down & focus & reduce stress. I find it's probably more helpful to me & my attitude than for them, but either way, it's good.
I also do not personally have any toys in the bedroom. I never have. I have had insomnia on & off myself all my life & read ages ago that if you do, you should do NOTHING in room but sleep. You need your body & mind to recognize your room as a place for rest only, so no homework, no play, nothing. I did find that change helped me some. It wasn't amazing, but better. So since birth I have kept sleep areas as only for sleep. I don't know if it's helped or not, but it certainly hasn't hurt us any.
And yes, no matter what, please know, it will pass. My youngest now is 3.5yrs & when I had my oldest I recall about this age being certain I totally broke him, he was ruined & every tough thing that happened was all my fault. Then he got older, the next one got to be that age & I figured out that toddler years are just really really tiring. I think I didn't realize that part would be so energy sucking. I knew the baby part was going to be serious lack of sleep, I didn't know that it could linger past that age.
So hang in there. I am sure with a little trial & error (and if nothing else, age) this will sort out.
