This is a fairly common problem for silicon AND Intel Macs running Monterey (and Big Sur too). I've pounded through every user option with my own to conclude- as objectively as possible- that there IS a bug(s) in Monterey (probably initially started in Big Sur) that causes this... and only Apple de-bugging macOS is going to remedy it.
Else, it's a game of "some enclosures work and some don't" and we can "buy, try & return, buy, try..." until we find one that does work. For an external M.2 stick want, I have discovered that OWC Ministack STX will remain stably connected to my Mac running latest version of Monterey. Others report other successes but I personally know THIS one WILL remain connected.
This is NOT an enclosure brand problem as there are plenty of posts by people here and all over the web sharing that the same branded enclosures will have some that work and some that don't... including me: OWC Ministack works, another OWC enclosure "unexpectedly ejects." No brand seems immune.
This is NOT a "need to upgrade to newer enclosures" scenario as you can identify with your new enclosure. In trying to resolve this myself, I dug out ancient, retired enclosures from all the way back into the 2000s for testing and some of those "just worked" (no "unexpected ejections") while other, much-newer ones unexpectedly eject. That also strongly implies it is NOT old vs. new enclosure firmware either: some of my oldest USB drives prob had firmware coded by Flintstone & Rubble.
People will pop in here and make you think YOU have something not set properly and/or blame the enclosures, cables, etc.- basically anything other than Apple- but you can try all of what they offer- as I have... and then some- and you are likely to find that none of it will resolve this problem
If you have an older Mac running a version of macOS BEFORE Big Sur (or a PC running Windows), I would bet pretty large if you hook the same enclosure via the same cable to it, you'll find that both cable and drive function normally. Generally, about a quarter of this kind of thread starts because someone just updated a pre-Big Sur Mac to Monterey and suddenly a drive that previously worked fine starts this buggy behavior. Some of those people need the drive more than they need Monterey so they downgrade BACK to the older macOS version and the drive is perfectly reliable again.
This seems to SHOUT where this problem lies, as it all but rules out cable, enclosure, firmware, default Mac settings, etc. If you don't have an older Mac or any PC, maybe a friend does and you can test a lot of variables by hooking it to the friends computer for a few hours. Magically, it is very likely to "just work," as you wish it would with your M1 running Monterey.
Of course, you too can try all of the stuff that will be shared <your fault, your wrong settings, enclosure's fault, cable's fault, hub's fault, etc that will get slung to redirect away from Apple having any fault at all>... and who knows: maybe your particular setup will "get lucky"... but I've been through ALL of this with extensive testing and I'm towards about 90% convinced this is Monterey bug(s) that only Apple can resolve when they get around to getting in there and making newer macOS work as well as pre-Big Sur macOS with external drives.
If you NEED that external storage with M1 Macs not giving you any option to go pre-Big Sur, change enclosures and maybe the next one... or two... or third one will be the one that delivers on what the U in USB means. Else, per my experience with this: fan suggestions to potentially solve this issue will have you in pursuit of Bigfoot or a unicorn, chasing a red herring, etc.
