According to SWISS.com’s Advance seat reservation info page:
https://www.swiss.com/gb/en/book-and...at-reservation
For SWISS European flights
- The standard seat is already included in the Classic and Flex rates. With the Light fare, you can reserve it for a surcharge from CHF 14.00 per leg.
- The seat in the preferred zone is already included in the Flex fare. With Light and Classic fares, you can reserve a seat for an additional charge of CHF 20.00 to CHF 25.00 per leg. The price is dependent upon the length of the leg.
- You can reserve extra legroom seats for a surcharge from CHF 30.00 per leg. The price is dependent upon the length of the leg.
The OP appears to have paid 20€ each for reserving seats on LIS-ZRH and selected 8A and 8B which are not exit row seats and presumably standard economy seats. He paid 17€ each for ZRH-BER which is shorter than LIS-ZRH. It is not clear from SWISS.com but I'm assuming that exit row seats (rows 10 & 11 on A321) are either extra legroom seats which carry a minimum surcharge of CHF 30.00 or preferred zone seats which carry a minimum surcharge of CHF 20.00.
Although it is not absolutely clear I am guessing the OP only paid for standard seats on LX966 ZRH-BER and therefore being "kicked out" of 11D and 11E which are either extra leg room or preferred zone seats.
I haven't flown on LX economy since before the pandemic but on LH European flights Economy Classic fares allow me as a SEN to select exit row seats without any surcharge. I wonder if the same applies to LX flights. If the same rule applied to LX I wonder if paying a little extra for Economy Classic may have made things much better for the OP.