Back in the day, if you bought a ticket with United and one leg was with Lufthansa, you could go to the Lufthansa site after booking and choose your seat. Now I see that functionality no longer exists on LH. It says I have to call (ugh) or pick a seat when checking in (ugh x 2).

Is there any way to reserve a seat in advance?

Details: I'm in Economy K class and I want to get a bulkhead or exit row seat for an 9 hour flight.

(PS: Mods, you can move this to the right thread as needed. I looked and looked, but the search terms had too many false positive results)