Never hosted a site on a VPS and I have no skills/time to manage myself
You have any ways to learn it, isn't hard to install a Control Panel to manage it, in Youtube you have many tutorials and videos and blogs also.
Is very easy to learn, you just need to learn and start about LAMP installation (learn that in youtube for example LAMP + Wordpress install vps ubuntu" you will have many videos showing how to do it.
Are you interested in learning? You have FREE videos in Youtube and Tutorials in Blogs for free, no costs! Just searching.
https://freedemy.co.in/details/udemy/Virtual Machine full localhost LAMP stack setup in minutes
Are you interested to have better skills and knowing what you are doing without any control panel and start from zero?
https://www.udemy.com/course/web-design-lab/ (No affiliate link) (English Videos - but you can search for you language)
https://www.udemy.com/course/linuxforbeginners/ (No affiliate link) (English Videos - but you can search for you language)
https://www.udemy.com/course/linux-server-setup-essentials-for-business-and-personal-use/
Isn't expensive, is very good to learn they focus in give the best videos for you, you can learn with Udemy, isn't expensive.
If you want to have knowledge is easy, just start searching. You can't paid? Youtube, blogs is your choice for free and no costs.
To start using VPS is required and EXPECTED to have a little know-how / knowledge about it. Which isn't hard. But you have everything I gave to you.
Can I host how many sites I want on that VPS?
No one can answers that question just because you ask. Why? Because no one knows with traffic you have, how many websites you will host.
Are that websites heavy? new?
And also with Hardware you are thinking your VPS will have? RAM, CPU (Cores) availability? You can't ask that question without saying which vps you are looking for. Hardware is the most important thing.
But answer you can host Unlimited Websites on VPS, it always will relay on which hardware you VPS have. 1GB RAM is not enough for 2-3 websites unless is static and small HTML websites.
I'm in EU country, which provider is the best for wordpress site? Vultr and DO are quite the same price...
Both are great, but if I was you. I should go with DO, because of their blog have a lot of tutorials and guides..
Look, you can also learn for free here
https://www.digitalocean.com/community/tutorial_collections/how-to-install-lamp
That's why DO is better, also Vultr isn't bad. But DO for me, is a good to go Hosting Provider in EU.
Cheers