I’d go and enjoy yourself.
The only thing that has changed is that Om is supposed to be more transmissible. But seemingly it’s not yet get a decent purchase in Europe. Delta was already quite transmissible, and you must have factored that into your plans.
Realistically, you could still very well have gotten symptoms, tested positive and been stuck. (No one would fly you with a definite case, even before.)
Get yourself a decent set of tests that are accurate in your favour. (Hint: LFTs are less likely to spot a positive.) And have a plan for how to make getting a negative result more likely. And take some NHS spares so you can get a heads up if the likely result before you use the real test.
In terms of the added trouble, they ask for evidence of the result. But some just ask for photos, which are easy, and (relatively) hassle free. But others want a video call. (Which with spotty hotel wifi, I would avoid like the plague.)
The worst case scenario is that you get unambiguously or seriously sick out there. But then your are in territory that the new rules don’t affect. For that case, you need to check your travel insurance. Do check though, because some don’t cover much that’s useful. On the other hand, we found that ours just treated you as “getting sick” (no covid special category) and then you get normal and appropriate treatment.
Sorry about the stress. Hope you can enjoy yourselves.