Combustion is just one of the factors that determines the strength (or weakness) of a planet, just because it's combust we can't say the rajyoga is nullified completely, it maybe getting other strengths like rashi bal, sthaan bal, digbal, cheshta bal, aspected or conjunct benefics, vargottama etc.
If a planet combust then his strength is weak then how he make any yoga by vargotam or other conditions
If a planet is having strength but in birth chart is in combust or in debilition then what we expect from that
Combustion is just one of the factors that determines the strength (or weakness) of a planet, just because it's combust we can't say the rajyoga is nullified completely, it maybe getting other strengths like rashi bal, sthaan bal, digbal, cheshta bal, aspected or conjunct benefics, vargottama etc.