I will help to answer your question.
at first you can use sendy.co , it using Amazon AWS. after all of settings, you have to request sending limit to amazon
or you can make your own private server using your VPS. free ip vps you can go to
https://www.imingo.net/fr/
or you can buy vps from
ovh.com or vultr.com(but I doubt vultr allowed you for email mass sending)
you have to learning about ip warm up for sending email!
read this for learning
ip warm up click here
you go to fiverr.com find people who can instal PowerMTA
what is PowerMTA? PowerMTA is aplication like postfix but it better than postfix, the can rotate email per ip, so if you want to have your own email mass server,my best sugestion you have to install it, if you cant install PowerMTA to your VPS. find people who can help in fiverr.
you dont need to much ip using powerMTA - 1-3 ip is enough, Dont BUY TOO MUCH IP if you dont need so much email submission, you have to warm up every ip you bought, or it will make your email go to spam, spam fillter, spam box
- using ovh.com or imingo.net for vps server
they allow anything in their server.
after installation you can your Mailwizz, I think that package is include in fiverr.com depend on the price and the seller offer their service
I hope it can help you