Maybe an unpopular opinion, but imho AWS, GCP and Azure are popular with startups because of their generous free credits, not because they are good tools for startups. As a startup you are typically better served by a DigitalOcean-level of complexity, and there are plenty of such offers in the EU (Hetzner Cloud, Gridscale, OVH, etc)
For Mailchimp you have plenty of competition, some of it in the EU (SendInBlue and Mailjet come to mind).
For payment processing there are also plenty of offers, Adyen is probably the biggest European alternative but there are countless smaller ones.
Microsoft Office 365 can be replaced by (shocker) Microsoft Office (the offline version). But most of your documents probably don't even contain PII and would be fine in Office 365 or Google Workplace. The exception is obviously email, but the market is flooded with E-Mail services from any country you like (and your preferred Hoster probably offers an email package too).
So I'm not really sure what part of the ecosystem we are missing here? European companies often have the smaller advertising budget and mindshare, but it isn't like they don't exist.