OK, you’ve got two potential things going on here.....
1. If it keeps pulling to one side when you release the steering wheel, that is because it is out of steering alignment OR it could have a tight brake shoe at the rear (or the tire pressure is not equal on both front tires). I would suspect alignment first (it may never have been properly aligned when built - it happens) so take it to an alignment shop and tell them to check it as a 1970 VW sedan EXCEPT that you want the front beam caster to be between 5° and 7° (because the car has been lowered). They’ll know what to do, but you should buy a couple of sets of VW caster shims (they’re cheap) and bring them along when you go. Alignment shops might not have them in stock because there is hardly any call for them these days.
While there, have them check the rear brake shoe adjustment on the side that it is pulling towards. If a shoe is tight it will cause the car to pull to that side.
2. While unlikely, it is possible that either the steering box is too tight OR you have a tight ball joint or tie rod end. Either can be checked by a competent old VW mechanic. The steering box can be accessed from under the front of the car and has two adjustments; one is for the center of the steering travel, and the other is for the ends of the steering travel and they are adjusted separately. Again, someone who knows old VW Beetles should have no trouble properly adjusting it.
They can also check for a tight ball joint with the car on a lift, then remove the wheel ends of the tie rods and simply steer the wheel by hand to see if a joint is stiff. There was a bunch of tight aftermarket ball joints from Asia a few years back and you may have one or more of those.
Tire pressure: Front about 20 pounds, Rear about 24-26 pounds. For spirited driving, add 2-3 pounds front and rear.
Lastly, remember that these little cars do not have power assisted steering so they tend to feel “heavy” in steering, especially in parking lots. Just the way they are.
Good luck!