A soft belly changes the angle. Heavy tits change how long she can hold herself up. A big ass in doggy is a gift if she can rest her weight on the bed instead of her arms. Use a firm pillow or a wedge. Talk when it hurts. Switch when she is done holding a pose.
Modified missionary
Pillow under her hips. Legs up or out. The belly shifts and you can actually get in. She can hold her thighs. You can lean on the bed, not on her chest.
Cowgirl
She sits on your cock and uses her knees. Depth is hers. You get the tits in your face and the weight on your hips. Watch cowgirl clips if you need the picture.
Supported doggy
Chest on pillows, ass up. She is not doing a plank. You see the whole backside and you can go pussy or ass. Doggy clips are that shape.
Spooning
Both on your sides. Low effort. Good when she is tired or you want it slower. Hand on her clit. Cock from behind without the full kneel.
Edge of the bed
Her ass at the mattress edge, feet down or on your hips. You stand. Gravity helps. No one is holding a yoga pose.