Those "R" part numbers appear to be specially coded.
For example, RVTDC144TUX appears to be a Toshiba digital transistor, TDTC144E. It would appear that "R" denotes some special category, while "V" denotes a transistor.
https://toshiba.semicon-storage.com/info/TDTC144E_datasheet_en_20201113.pdf?did=36376&prodName=TDTC144EIn the case of your coil, the "L" seems to be associated with inductors and filters. This would suggest that the base part number is O9U034T-T, but that still doesn't get us anywhere.
As for its function, the coil appears to be part of a DC-DC boost converter. Q24, Q25 and Q26 constitute an oscillator. The boosted output voltage appears at the junction of C112 and D10.
I can't see enough of the circuit to be certain, but it appears that D8 provides the supply voltage for the linear regulator at IC 5 (S81221SGQUT1). That's a Seiko-Epson 2.1V LDO regulator.
https://datasheet.datasheetarchive.com/originals/distributors/Datasheets-30/DSA-595487.pdfIn short, it appears that the 3 transistors constitute a dual switchmode supply. If so, then it should be possible to replace that section with a modern supply module, or two.