ContraDix I'm currently downloading the manjaro budgie iso of the 5.15. Would the guide made for checking the iso in Solus, work for checking the one of manjaro?
Yes, you could do it the same way. But if you've downloaded that .ISO file from the Manjaro official web site, there's almost no way that it could have been tampered with. I've never tested a file from an official distro web site, and I've never had a problem with it.
You should be able to use the same USB stick you used for Solus Budgie. Whatever app you use to write the .ISO file to the USB stick should overwrite the Solus content with the Manjaro content. The Manjaro Live session will work the same way as the Solus Live session. You'll have an option to install the OS on your computer.
There's no reason to leave this forum, if you have any interest in trying Solus again later. And I'll even be glad to help you get started with Manjaro, if you need it. Budgie is pretty much the same, no matter what distro you use it on. Just things like the package manager, that have nothing to do with the DE, are different.
And if you check this forum occasionally, you'll know when it's safe to try installing Solus again. Please let us know how you get along with installing Manjaro. I suspect it will go smoothly, but if not, there are other good Budgie options I could recommend.