How to test the plugin on different servers and settings?

Hi,
I just uploaded a wordpress plıugin to envato ( https://codecanyon.net/item/wp-mega-push-notifications/17126729 ) and had to handle different feedbacks,
Of course i have tested the plugin on 1 server but i realized that many customers uses different proxys and many other settings.
How do you test your plugins for different scrnarios which you can not re-produce? is there a testing platform or a beta tester platform anything else?
Thanks for feedback

I have 3 in house servers with different server configurations, different PHP versions. And I have 4 servers online with different hosting companies. You can find some free hosting offers, but such servers are very limited and you will not be able to test everything. Best thing is to have few servers with different companies.