Even if you can book a holiday to the EU, you won't be allowed to enter the EU.
www.bbc.co.uk/news/uk-46627083
Because of Covid, travellers from most non-EU countries can't visit except for essential reasons.
After 31 December, the UK will no longer be treated like a member of the EU, so becomes subject to these rules.
The only non-EU countries exempt from these restrictions are those with very low infection rates, such as New Zealand.
Let's hope that things improve for this summer...