Using custom ROM with unlocked bootloader

I’m an android user and want to flash custom rom for privacy n securtiy reasons. I don’t have a Pixel phone , as we know pixel are the only devices which support relocking bootloader and verified boot but what about other phones? Is it safe flashing a custom rom and using it with unlocked bootloader? Is there any ways to be secure? Or should I avoid it? If I can proceed then how can be secure afterwards? Plz I need clarity on this guys…
Thank you.

DivestOS also features relocking bootloader/verified boot (DivestOS Mobile) for devices other than Pixels, see if they support your device.

Otherwise, using an “de-Googled” ROM without verified boot is generally seen as sacrificing device security to gain some privacy from Google. If you are unsure whether the trade-off is worth it, you should probably err on the side of security. Of course, only you can evaluate what works best for your threat model, you can always read up on the AOSP documentation to better get a sense of what benefits verified boot provides (Inicialização verificada  |  Android Open Source Project).