Unable to create more than 2 lightsail instances in any aws region

Hello.

So I was wondering what is the actual limit and does it vary from one aws account to another and/or one region to another within same account? Where can I find up to date documentation around it?

As stated in the documentation below, Lightsail quotas may be set lower than the number displayed on the quota screen depending on your AWS account.
I think the extent to which it is configured varies depending on your AWS account, so we recommend that you open a case with AWS Support under "Account and billing".
Inquiries under "Account and billing" can be made free of charge.
https://docs.aws.amazon.com/general/latest/gr/lightsail.html#limits_lightsail

New AWS accounts might start with quotas that are lower than those described here.