Hi @Drb welcome to the /e/ forum.
This is the Install page for fp5 Install /e/OS on a Fairphone FP5 - “FP5”. As you plan to lock the bootloader you should choose official of the Different Build Types available. Android 15 official has not yet been published or announced at this point but it is expected. Any update on this will be seen in Development Updates. [1]
Before you start please be sure to understand the anti-rollback hazard and I suggest take a screenshot of your Android SPL as shown in Settings > About phone > (tap on) Android version.
(There is also (for the adventurous) Web Installer linked from
Info about Fairphone FP5 - FP5. Do not expect Android 15 at this time until this is reported available.)
- Do not hesitate to open a new thread if you need further support.
[1] a15 when available will appear here /e/OS official FP5 download