Many drugs are TAAR1 agonists.
TAAR1 agonists cause serotonin release. Serotonin release is gonna make you feel good.
Tramadol is a weak TAAR1 agonist & it use to do wonders for my depression. But so did heroin. But it's a much weaker TAAR1 agonists compared to something like methamphetamine.
So TAAR1 agonists would theoretically offer some relief from WD's, especially amphetamines as they release dopamine too. But then once you stop the TAAR1 agonists / amps, you'll just be crashing from stimulants AND going through opioid withdrawal.
OP, I'm confused. You said you quit fentanyl & got on methadone, but then didn't even feel wd's from the methadone? I'm assuming you're back on fentanyl then?
If you didn't even have withdrawals from the methadone, then why did you pick up opioids again? I mean it sounds like you want to be done with them altogether, but you must have gone back to using fentanyl. If you had no WDs stopping methadone, I'd have just never touched another opioid & moved on with my life. So the real question is something you need to look inside yourself for. Are you ready to quit opioids? Or are you looking to keep using opioids but just want off the fentanyl train? Both are valid reasons, but the paths to achieve either of those outcomes can look very different from one another.
The best thing honestly for a person in your situation would be to maintain on a potent opioid. But thanks to the ignorant world we live in & the drug war, there aren't much options other than Suboxone & Methadone. I don't know of any prescribed opioids that reach the same potency as fentanyl. Not any common ones anyway. Except for buprenorphine. Suboxone (buprenorphine) is technically 40x more potent than morphine, but it's only a partial agonist, so there isn't as much pain relief or euphoria. And it lasts an incredibly long time. But it still has that really high potency where it attaches & sticks to your opioid receptors like glue. It's also a partial antagonist as well, so in high enough doses, it can blunt some of the effects of fent or other full agonists you might use, making them feel less "enjoyable". Maybe you'd have better success with something that potent (although it's only a partial agonist) compared to continuing your fent use? Some people prefer Subs over Methadone & vice versa. It all comes down to your own unique physical make-up & chemistry.
Are you using street fent? Cause if that contains tranq or whatever garbage they're putting it now a days, you could have withdrawals from that. For that, you'd need blood pressure medication. Most likely alpha blockers. But you'd need to be careful & taper with those, because you can get severe rebound high blood pressure when stopping.
The reality is, no matter what you switch to, you're still going to have to suffer for a few days until your body adjusts. And don't let drug war conditioning make you think that being addicted to a safer opioid is a still a "bad thing". Better to be addicted/dependent on a legal opioid versus risking your life with fent/street opioids forever.
I always tell people the best way to beat an addiction is to get addicted to something else that makes you feel good, but causes less problems in your life, whether it be your mental well-being or physical well-being or both. I'm sure as hell physically & mentally better-off taking buprenorphine/opioids than I would be if I was still a daily raging alcoholic.
