Going out for a long bike ride where you encounter no other humans is fine; encouraging going out on a long bike ride is fine. Going into shops etc (either for supplies or validation) is the only thing I see that's problematic.
Identical discussions were carried out during the first lockdown and AUK decided to suspend validations. I don't see why this time they should act differently.
There has been no change of risk assessment for DIY and perms, as far as I am aware and there is no obligation to be "self reliant". So, the expectation is that randonneurs will go a long way and they will stop in shops in areas which are far away from their postcode, all of which is against the rules, as I understand (don't travel outside your area).
Then I am sure it is perfectly possible to do 200 km, whilst staying in your area and obeying all the rules with a bit of imaginative mapping, but AUK cannot monitor that... so no validations is the only grown up option.