Meh, I don't think it's a post-covid thing. I graduated in 2009 and 2 of the 4 other girls I lived with literally never attended a single lecture, just watched the power points. They all got 2.1s. This was a high ranking RG uni.
I don't think the way unis work are really set up to reward effort. It is really easy to get a 2.1 and incredibly difficult to get a first.
In my second year I went to every lecture, tutorial, planned my essays well in advance, did the background reading, etc. Received a mix of high 2.1s and low firsts, with an overall mark of 69 - so just slightly too low to get an overall first.
In my third year I had an issue with my student loan and also had a bereavement which meant I just could not be bothered - I worked nearly full time, partied more, barely went to a single lecture, and half heartedly dashed off my essays last minute. Still got (low) 60s for all of them = the same 2.1 grade overall, as did 90% of the class. I'd say less than 5% got firsts, maybe 5% got thirds.
If I'd known how hard it would be to get a first I would have done the same in years 1 and 2 as I did in 3 - would have had more fun and accrued less debt!
While a few lecturers were genuinely inspiring and interesting, with some of the others I learned nothing more from an hour in the lectures than 10 minutes reading the powerpoint. Particularly in humanities type subjects, there's no actual reward beyond the love of learning the subject in putting more effort in. At least in vocational subjects there's the chance you will actually use what you're learning in your subsequent job.
Other countries (like the US with the GPA) differentiate between different grades.
I think universities have to accept some blame - pack students in in huge numbers, minimal tutorials or small group engagement just giant lectures, charge them a fortune, don't bother with interviews etc for acceptance but just go off statements, treat them like shit during covid, and then be surprised when they treat uni as a purchase rather than an experience.