i agree , definetly starter motor my van exact same fault for years , replaced the starter all working well starts first go at the key when cold or hot or frozen
the communtator on the starter gets gunked up and scored and worn the brushbox fails on one side of the starter causing charging and power voltage issues to turn the starter with enough oomf (power)
new starter ebay non gen 3months no probs $100 AU im happy
Cheers
Wazza