Randomness of random.randint() vs uuid4

I have used uuid4 since now in my project database (still in development) but I am now thinking about switching to random bigints for PK.

Can someone tell me, how much worse the randomness of randint(1000000000000000, 9007199254740991) (javascript safe) vs uuid4 is?

I bet, I am using the term randomness wrong here. What I want to achieve is, that I do not have continous but of course unique ids in my DB, thats why I used uuid until now. But because I ran into a lot of troubles I would like to switch to integers now and would like to know how much "more random" uuid would have been