If you want it cheaper, I also have good experiences with Motorola phones. Unlocking requires you to register, but you can use a throwaway mail account and it has worked for me so far many times. Just make sure the device is officially supported by Lineage, I have very mixed experiences with unofficial ports.
Stay clear of anything from Xiaomi. Unlocking is a nightmare and you have to wait weeks to get your unlock code.
0. https://calyxos.org/news/2022/07/06/oneplus-android-12-reloc...
First time I needed to wait 2 weeks. Second time, I made the mistake of using the same Mi account and had to wait 4 weeks, because I did not know each time you unlock something your waiting time doubles. If your phone for whatever reason looses the Mi account connection, everything gets reset and you start from scratch.
It's not the end of the world, but 300$ will also give you a pretty decent Motorola Moto G phone, which are way easier to unlock (all you need is a mail address, and you'll get your unlock code instantly).