Have you tried clarifying? You might do that, followed by the PT, and then a DT. Then see what your results are.
My hair is like yours, to down extent - not fine but not quite medium, maybe a mix of both, yet it behaves as fine hair, for sure.
My hair responds well to protein, but that blessed balance is hard to get! It dries out, too!
So I'd say clarify, then do your PT and DT!
2c/3a/3b, Fine/med, Dense, high porous, & normal elas.
Lo-poo - Renpure Keratin, SMR, Giovanni SaS
clarifying - mix Johnson's H2T with low poo
Co-wash - Suave Nats. clar. or coco.
RO - GVPCB, Ion Eff. Care, TN.
LI - SMR, Cure Care, or RO
Seal - MO or Jojoba
DT - + honey, ACV, & EVOO to SM masque & GVPCB
PT - Gelatin!, CNPF
Styling - FSG, AIF, BRHG, LALS/PS, GF curl spray gel, SM Souffle/Smoothie, LOOB
Oils - MO!, EVOO, jojoba, GSO, SM Elixer, EVCO, VO5 Hairdressing