I've been working in Digital Analytics for 10 years as a freelancer for SMEs and implementations for billion dollar companies. I am very comfortable saying for 99% of websites there is no better alternative, paid or free to GA4 and based your requirements you fit into that 99%. Happy to debate this in comments.
edit: I believe the 1% exceptions are:
- if you are a are a tech company
- run multiple Adobe tools (CMS, CRM)
- have niche privacy requirements
- have an app