refind-theme-regular VS Icnspack-Builder

My boot manager is refind (not grub), and the theme is refind-theme-regular

You can have multiple boot-loader partitions and it will detect them all without any additional setup from user. So if you are dual booting and accidentally formatted boot-loader for one operating system the other will still work. This happened lot of times for me. I accidentally deleted windows option when reinstalling linux a lot. You can also boot from usb directly from refind within needing to go into bios. You also mentioned config file for systemd being simple. Refind also has config file similar to that. And it has theming. I use this theme https://github.com/bobafetthotmail/refind-theme-regular

Theme: https://github.com/bobafetthotmail/refind-theme-regular

I actually managed to get it to work both ways: I can boot each OS in a VM from the other. A handful of scripts inside each detect the VM and make some changes appropriately (like disabling certain startup apps and services that I already have in the host OS, disabling some fancy graphics that like to glitch out in VMs, etc.). And because I like to over-complicate things, I set up static IPv4s, so I can for example connect to Linux with the same IP, not matter if it's in a VM or running on bare metal.

Also, regarding hating GRUB: take a look at rEFInd. The themes are way better [0] and it can autodetect operating systems so not only is it harder to break your system with a bad config, it'll detect USB boot devices as well so you don't have to mash F11 or whatever if you need to boot from one. It also has mouse support and (in theory) also touchscreen.

[0] https://github.com/bobafetthotmail/refind-theme-regular

Finally I installed a simple minimal theme https://github.com/bobafetthotmail/refind-theme-regular and added the OpenCore logo to the icons folder.

I use this one.

For me, Refind it's the best bootloader for dual boot. With a theme like this it's quite pretty : https://github.com/bobafetthotmail/refind-theme-regular

I use this rEFInd theme and convert them into .icns

I would like to switch from grub to rEFInd because it has this specific theme but my main concern is: will it have an option for booting into snapshots? is a handy feature with something breaks on a update but if not that's fine!

If you want to theme refind, I suggest this beautiful theme which has distro icons for all operating systems: https://github.com/bobafetthotmail/refind-theme-regular

Using a background from BlackOSx Gallery: BlackOsx Themes in particular BsxRedOldApple: RedOldApple it is noted in their readme that only one background should be in the folder as there are several different aspect ratios and rez's in the background folder. Since the machine I will be using is an HTPC attached to a 4K Roku TCL tv with a native resolution of 3840 X 2160 should the background icon be at the same aspect ratio when converted to a .PNG and double the rez ie 7680 x 4320 then converted to .ICNS using Icnspack-builder (IcnsPack-builder)? My current background at 5120 x 2880 converted is considerably smaller than the viewing area on my TV but fine on my 2K monitor. (2560 x 1440). Is there a max rez, and is 7680 x 4320 safe?

Follow dortania’s guide and after that use icns pack builder to convert your desired images into the correct format and replace them in the resources/image folder

You can also design the one missing if you want, or grab any other icons you like to replace these buttons (and use Icnspack-builder to convert the PNG into ICNS files)

https://github.com/chris1111/Icnspack-Builder uhm... actually, you can use this app by chris1111. Just push .png image to it, it will automatic convert to .icns, you will get the background

You have to use this on Github to make the icons. Then be sure to make the icons exactly 256 x 256 pixels.