I’d say it looks loose in your push test too. That’s the hard part about something that’s a judgement call.
My personal recommendation would be to remove the belt, tighten one of the bolts about 1/8"-1/4" then reattach the belt using the push method…and then never undo those bolts again.
I’ve never adjusted those in the ~6+ years I’ve had my machine and it does just fine!
Yeah I broke it removing the carriage head so it needed to be replaced. I tried the push method and not having any luck…my old one fits perfect and works so im very confused.