Success! The DSO-X 3024T is now unbricked!
Thank you for getting me on the right track. The thing I missed was that the v2.35 firmware in the "titiris method" didn't include the T-series.
I managed to find an old firmware (04.08) for the T-series and did the following (a few changes to the titiris method).
1. Extracted the recover.nk.bin.com from the .ksx (renamed it to .cab first)
2. Ran the UnKsx.exe tool to decrypt the recover.nk.bin.comp (Thank you user: abyrvalg)
3. Extracted nk.bin from the decrypted recover.nk.bin.comp with bincompress
4. Got the length of nk.bin with viewvbin.exe
5. Converted nk.bin to nk.nb0 with cvrtbin.exe
6. Connected to the scope via 3.3V Serial
7. Stopped the boot sequence
8. Entered the "loady 0x0361000 115200" command at p500> prompt
9. Transferred the nk.nb0 via YMODEM
10. Entered "go 0x00362000" command
And, boom!
The u-boot sequence finally looked much better and the scope started! Once started it complained that the FW was corrupt, but I just took the corresponding .ksx firmware I used earlier, put in on a USB and ran the prompted FW-upgrade. After upgrade the scope started and worked 100%. After this I grabbed the latest firmware (7.60 from 2023) and made yet another firmware upgrade.
Greetings from a happy user