If I had the opportunity to stop working and keep being paid half or third of my salary, that would be an interesting consideration, where I'd probably work but work less, and I know people who'd do differently in both directions; the doctors would still keep their patients, but some struggling people would stop working for pay and work on their dependents (both kids and elderly/sick parents).

The whole point of UBI is that it keeps incentives for working, as most people - especially the most valuable employees - do want much more than a basic income, - and also supports partial employment (as opposed to things like means-tested welfare). What it would change the most is the situation regarding "shit jobs" which are both poorly paid and undesirable; and if the desperate workers get some alternatives, then these jobs would have to pay more, improve conditions, or not get done if they aren't that needed; and that seems a good effect to me.