How to prevent separation anxiety + any other tips appreciated

Hello,

My now 13 week old labradoodle is doing pretty well with crate training (goes in when I point towards the crate, happily licks his kong, finishes it and then wails for 2 minutes and goes to bed). He spends almost every nap in the crate (with crate covers) except for the afternoon where he sometimes sleeps on the cold tiles. We have left him periodically with the crate covered for 1 -2 hours (after a pee and poop and food and toys etc) – but need to slowly transition to leaving him home alone for up to 4 to 5 hours when I start work in feb (he will be approximately 5 months) for 3 days of the week (every other day someone is home).

He has a puppy proofed room that has space enough for crate, pee pads/grass pad (I know this holds back on out door potty training, but id rather him do it in a designated spot then on the floor) + enrichment (approx 2 x 1m space not including crate). He is super attached to me and follows me everywhere and I do not want this to eventually lead to separation anxiety lol. In terms of his training, he toilets outside AS LONG AS we take him straight after every crate nap and after some intense activity (if not he just finds himself a nice carpet). He sleeps through the night most of the time, can do basic commands and we are working on more important ones like leave it/drop it etc. He likes to run away with shoes and socks and honestly anything that ISNT his toy he grabs and runs and chews:).

Any tips on how to progress from here to more independence (and get him to not whine and bark in his crate 10 minutes after the kong) would be very much appreciated!

Also: I have tried the whole give him an enrichment toy and leave for 10 seconds and slowly progress. My boi is up to maybe 20 to 30 seconds but often comes to stand at the door, waits for me to return then goes back to his enrichment activity. We have a set of baby gates that we are planning to install over the weekend so he can learn to sit behind the gates and watch life outside but not necessarily always be involved (let me know if this is a bad idea). First puppy so I'll take all the tips I can get!