Never had a key or a game revoked when using CD keys and I've been using them for almost 12 years now. Sorry but the simple mention of "I care not if people have got the Beta or not, certainly not hurt " tells me you kinda are. Just because they are not approved doesn't mean they can't include beta and there's nothing dodgy about CD keys, if they were do you think they would be allowed to trade within the UK or us being able to connect to their website? Anyway from this article by The Mirror newspaper says nothing about approved list to get beta but if you pre-order from Steam, Epic, Microsoft store etc. I got a steam key from Cd keys so It's classed has pre-order. Here's the article Football Manager 2023 Beta available now - Here's how to download on PC and Mac - Mirror Online. To be fair not much has changed that really warranted a new game as such, whilst there as been some nice new additions, most of it seems the same as FM22.
Also here's some information that you seemed to have missed with regards to CD keys being dodgy: Is CDkeys Legit and Safe? Or, is it a Scam? | The Legality