Is this a very sloppy holding pattern or something else?
It does indeed look like they are not correcting for wind. The current wind over Belarus at 10km altitude looks like this:

(screenshot from windy.com)
That is consistent with the direction in which they are drifting. Such a flight path is not a normal holding pattern, which is based on a holding fix. While wind might push the aircraft somewhat off the nominal racetrack pattern, they would at least regularly overfly this fix (although modern RNAV systems are pretty good at compensating for wind).
I can only speculate on why they are flying like this. Most likely they are not holding at a specified fix. They might have been instructed to hold at current position by ATC, probably while they figure out if they are still allowed to fly into the EU, after the European Council has called for a ban:

The European Council:

[...] calls on the Council to adopt the necessary measures to ban overflight of EU airspace by Belarusian airlines and prevent access to EU airports of flights operated by such airlines;


(europa.eu)

Update: It seems they are returning now:

(flightradar24.com)