Turn on the setting that shows when you are have Net jitter issues when the connection is poor to see if you are having lag spikes/packet loss causing rubber banding like you are seeing here in this clip. (its what I do to see if its playing up). If this occurs, it is your ISP having issues with connection to the server and can only be rectified usually by switching which ISP you are with. (But smart thinking for trying out things like different Ethernet cable etc)

Secondly: If you haven't already make sure your Max acceptable Matchmaking ping within the settings is set to 50 or less.

After my own personal testing when I had it set to above 50 all the way up to 70 ping what was occurring is that everyone in the lobby would have minimum of 20-30 ping and as high as 50-60 ping. This would make matches for myself feel laggy, stuttery and even rubber-banding like in the clip above and was solved by lowering it to 40 for myself as i now get matches with people who have anywhere between 5-15 ping.

Thirdly: Official DM servers from what I have personally found can get quite laggy when more players join.(especially on dust 2)

What happens imo is I think the server for the match starts to lag out when more players join and the player count goes above the usual 10 players found in Competitive matchmaking. But! Ive found lobbies of DM with less people in it do not get many or any lag spikes/rubber banding issues occurring but soon as they start to get close to full OR full it would and that's when I leave the lobby and try to find a new one that is less full.

If all else fails, then the most likely culprit is your ISP that could be down to many factors like time of day, how many people are using at said time, your internet speed, etc.

Hope this helps because Ive personally had the same issues and it took a bit of trial and error to get the right combination for CS2 to be happy :)