... it appears to stop during the paypal conversion
If there is no error displayed, It does not end the task at the ubbt_PAYPAL group. It completes working on that table, then it processes the next items in a group containing ubbt_POSTS (the next table group, alphabetically) and works on that for what may seem like a long time to you. You did say your tables were within the 1.5GB range. just wait until it completes. If there is an error during the process, a notice will be displayed. If there is no error, the tool is still working.
Am I supposed to be worried
Databas was 1,25 GB is now 1,09GB
When it completes, you may notice that they are reduced in size. From latin1_swedish_ci to utf8mb4_general_ci, your previous character-set collation index column value had 255 characters.
In the case of utf8mb4, 1 character = 4 bytes, the limit is around 191 characters. So only 191 characters will be added to index, other characters will be truncated from the index. (255 vs 191 = 64 fewer)
When you change encoding from latin1_swedish_ci (at that time it was 1 character = 3 bytes) the indexed limit was around 255 characters. It means your column value, all 255 characters, will be moved to the index without truncating.
For utf8mb4_general_ci, the characters from the index decreased from 255 characters to 191 characters, so the total index size was also decreased.