When my once so-thick I couldn’t get a hairslide to stay in without it popping open immediately had thinned to old lady thickness by age 33, a fine-tooth comb sufficed to tame it.
One of the immense joys of discovering hair replacement at Aspiration was that I now needed hairbrushes again. Even de-tangle combs!
I attach a picture of the best design of of wide-intertooth comb I have found for minimising your new hair breakage and damage to any extensions and systems, though it works pretty well to tame 100% naturally-growing manes too. This type of detangle comb used to be all the rage and you could buy them in several funky colours in your local Boots but sadly it now takes the internet to track one down.
If you also want a brush, the Tangle Teezer is the best one of those I’ve found, though do try to buy one with a handle if you don’t want it slipping out of your hand like a bar of soap every minute or so to land with a plonk in the bath as the actual holding bit is not so well-designed.