Been making my own homemade mayo (recipe below) for a decade, and I use regular light colored olive oil (not extra virgin, that's too grassy), but any non-seed oil will do, if it's flavorless. Make sure it's not cold, but room temp.

Stick blender mayo

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1 whole egg +1 yolk

1 tsp Dijon mustard

1/4 tsp garlic powder

1/2 tsp salt

2 T vinegar or lemon juice

1 cup refined olive oil

In a jar whose interior bottom just fits a stick blender head, place egg, add rest. Fit blender head over eggs. Add oil slowly.

Blend, pulling up gently