1) “I was told it was necessary to grab him and pet him so he would get used to being held and to me.”
As you probably already realised, grabbing and petting him when he doesn’t like it is indeed counter productive. While there are exceptions, a majority of bunnies don’t like to be held at all, so try not to do that unless it’s absolutely necessary. They are not “cuddly” animals in general. If your bun isn’t a fan of cuddles, the most you have to do is to get him to “tolerate” being picked up, but do this in his own time and when you’ve gained enough trust.
2) “I was told to feed him unlimited alfafa hay and alfafa pellets until he reached 6 months old.”
They need alfalfa to grow, so you can keep feeding the pellets for now. Like bam has said, a lot of people start their bunnies on grass hay (e.g. timothy) since young, so they become less picky after growing up. Many bunnies would refuse timothy hay when they are transitioned to that since alfalfa is tastier, so it makes your job easier to start giving him timothy hay now.
3) “Should I get him a bigger cage or a different “house”?”
Cages are only a no-go if the bunny is cooped inside most of the days. If your bunny is free to roam, then a cage is fine
In fact it could act as a safe cosy place for him to retreat to if he feels endangered.
4) “I also read I have to trim his nails and clean his ears for the monthly maintenance”
Nail trimming is necessary and if you really aren’t able to do it, you can always get him to a rabbit savvy vet – most of them charge only a minimal fee for nail trims. I don’t think ear cleaning is necessary if his ears aren’t infected or anything – they do the cleaning themselves most of the time. But you should probably just check and look inside them occasionally to see if there are any abnormalities since lop bunnies are more prone to ear infections and such.