Yes, that is generally the case. As a general rule with an Android phone reflashing the OS itself or the bootloader carries no risk of bricking the device (meaning making it impossible to recover without specialized hardware and/or opening up parts that were not intended to be opened).

There are plenty of ways to "soft-brick" a device such that you might need to plug it in to a computer, and adb/fastboot can definitely be a pain in the ass to use (especially on Windows), but if you have a device with an unlocked bootloader it's very rare to be able to actually brick the device while doing normal things.

Now, if you're doing abnormal things like reflashing the radio firmware you can absolutely brick some devices there, but you don't have to do that just to boot an alternative OS and generally shouldn't be doing it without very good reason and specific knowledge of exactly what you're doing.

I'm not going to say there are no devices where the standard process to flash an alternative OS is dangerous, but none of the relatively common ones I've ever owned or used have been built that way because OEMs don't want their own official firmware updates to be dangerous either.

tl;dr: It is sometimes possible to brick a device by flashing the wrong thing incorrectly, but the risk of doing that if you are just installing an alternative OS through a standard process is basically zero.