Matic, mistakes happen, but generally people with a history of success on Upwork don't get suspended for no reason. There are millions of freelancers here, so when you see 20 stories of bad experiences, it may seem like a lot, but it's really a tiny fraction.
That said, going "full time on Upwork" is probably a very bad idea. One of the keys to running a successful freelancing business has always been to balance your work in a way that keeps the ship stable if one client suddenly fires you, dies, shuts down the business, etc. Clients will always come and go.
Now, Upwork isn't a client, and you'll probably have a lot of different clients on different schedules through Upwork, but there are still a lot of things that could abruptly go wrong when you're routing all of your work through one platform. Probably the most common would be a client doing a chargeback or using a stolen credit card or whatever. When that happens, your financial transactions are frozen pending resolution. Maybe you have $1,875 in your account and $60 of that came from the shady client--doesn't matter: you can't access any of that money.
Then there are the bigger things--Upwork goes out of business, or changes its business model in a way that no longer works for you, or becomes inaccessible in your country, or simply loses significant market share over a relatively short period of time and the jobs dry up.
None of this is a problem with Upwork or meant to scare you off of the platform. Upwork is a great source of clients for many freelancers, and these issues could arise with any single company. But, putting all of your eggs in one basket has always been risky for a freelancer, and when that basket is a single company in a volatile market that happens to be housed halfway across the world from you...
Think seriously about diversifying.
