This is a kind of old thread, did you end up trying it & if you did do you want to share how it went?
Idk if you're still looking for responses on this but I'll share mine anyway in case there's someone else who has the same question. This is going to be long because I want to give a realistic idea & be honest about what it's like for me. I wrote most of what I'd want to know if I asked this before I started but if there's anything someone wants to ask I can try to answer.
I volunteer right now for 2 chapters of a grassroots activism group (& anything else by the members I can attend outside of the group). I want to volunteer for more but the movement in our area is limited right now. I also want to volunteer for one of the animal sanctuaries here, I'm prepared to do the gross parts of volunteering at a sanctuary, but I can't get to them, hopefully in the future. It's helped me a lot. I'm really passionate about what we fight for, it makes me feel inspired & less powerless. What we do is contrary to ~99% (98% if we're being optimistic) of the global human population, it feels really frustrating, volunteering lets me see people who get it, it's less lonely & a break from what we have to deal with every day. More personal is I feel like they're the only ones who treat me as an actual person. They don't care about how I look, how I act, my conditions & limits, all they care about is that we're fighting for the same cause & appreciate all the help they can get.
Idk if solo activism is considered volunteering but I do that too & that also helps in many of the same ways. Less powerless, inspired, gives me something to do, gets me away from home. Both solo & group forced me to get better at talking to others & understanding them, I've been forced to be a kinder person. I've learnt not to judge others as quickly & understand "Even good people are great at making bad decisions." I have to read scientific articles, statistics, writings/books, listen to debates, etc. That makes me feel less dumb & this new knowledge helps me in other ways I didn't expect. Both can also make me feel bad, group tends to be easier because there's others with you. The bad would be unique to activism not volunteering for something "normal." The bad limited to social activism (there's many forms of activism you don't talk to others so these aren't problems), you get people saying rude shit to you, you get people saying truly awful shit about others & justifying horrific things/bite the bullet, you get people claiming false anti-science shit & fallacies you hear every day & it gets annoying, etc, & through all that you have to stay calm & patient (not easy for me). But when you get a good discussion/reaction, it's one of the best feelings in the world & make all that shit worth it. I walk away from it feeling great, 1 of the only times I don't hate myself. Even better is when someone lets me know they changed after talking to me, every time that's happened I felt like I was on the best drug in the world for a few days straight, it's not common though usually it's 1 talk & they change later & you never get to know, so we can't let it give us unrealistic expectations or burnout happens. Supporting other activists is also really important to avoid them getting burnout & bad mental health. It helps me knowing I'm helping them & that helps who we're both fighting for too.
This started for me during the pandemic, all these experiences have been limited because of that. I think once restrictions are loosened & I can do more, more often that it's going to make me feel even better.
Decided recently I'm going to start picking up the litter around this area regularly. I don't enjoy trash it's stinky & gross, but it gets me outside & to take a walk, gives me something to do, I'm helping others.
If it's something you're not passionate about or there's too many people you don't like in the group it might not help you feel better. There's other things I've volunteered for that stressed me out a lot, didn't make me feel good, none of them were related to activism. If you're volunteering for activism instead of a hobby then I think it'd be less likely to give up even if you don't like the people there but you have to expect different challenges.
TLDR: Volunteer for activist groups & solo activism helps me a lot but it's not a magic cure & there's still hard stuff you have to deal with. Volunteering for a hobby you love can make you feel good too & avoid most of the bad related to activism but in my opinion it lacks the amazing things about activism & people there might be more likely to piss you off so you return to being a NEET. I strongly encourage others trying some forms of activism for whatever matters the most to them. I know a lot of people on this site are passionate about Right to Die, maybe whoever is reading this would be interested in doing activism for that as an idea.