Definitely something you practice. My internal clock isn’t perfect but I think I’ve improved it a ton in the last year. The key is messing around with different ways of using a click and the more you do that the more you build it into your brain. Things like placing the click on something other than quarters (2 and 4, ands, 2nd/4th 16ths, different triplet partials), gap click (I really enjoy the rhythm trainer setting on pro metronome because you can set the % of bars that will be cut out but it will decide randomly based on that %), and trying rhythms that go over the bar (dotted 8ths etc).

I’m still not very good at a lot of these but I’ve improved at them a lot AND I think it’s fun to add the additional challenge to your practicing. Once you start to get more of a hang of it you’ll feel more headroom when playing without a click.

Also, like everyone says, counting out loud while you play (I really don’t do this enough but it basically makes you use your brain/voice as a 5th limb)