Edit: I found https://european-alternatives.eu/alternative-to/cloudflare , which lists among others: https://bunny.net/ , https://www.keycdn.com/ , https://blazingcdn.com/ , https://www.myrasecurity.com/en/product-content-delivery-net..., https://www.leaseweb.com/cdn . If anyone has any personal experiences with any of these please share.
The main "gotcha" is that there's no free plan, it's a minimum of $1 per month, you pay for usage. In practice it's very hard to spend more than a dollar in a month.
Which is weird. CDN requires massive distributed footprint, which inherently provides the enormous network capacity needed to absorb DDoS attacks. So why aren't they offering the same thing as Cloudflare?
European CDNs should form partnerships with both European IXPs and Tier-1/Tier-2 ISPs (like Orange, Deutsche Telekom, etc.) to see what exactly is missing to do both unmetered anti-DDoS and global CDN/caching.