It doesn't mater if the roots get tangled. We can just cut the roots or gently pull them apart when we repot them anyway.
It is possible to separate these at this stage but be careful. Easy to damage those tender green stems. Usual advice is as above- wait for the stems to turn slightly brown and harden a bit before repotting.
Seedlings can safely be repotted any time from when they appear above the soil until several years old so timing is not critical.