Potty Training New Dog

Neutering shouldn't make a difference.

You want to set him up to succeed by taking him out even more than he needs; for example every hour or so.

Toilet training happens when two things come together - the ABILITY to hold the toilet, along with the DESIRE to hold it in order to earn the reward for doing so.

When he toilets outdoors make a huge fuss (never mind the neighbours, act like outdoor toileting is the best thing you have ever seen) and reward him with a high value treat. Do that immediately, don't make him come to you for the treat so he is clear that it's for toileting and not for coming to you. The idea is that he wants to earn the treat enough to hold the toilet until he is outside. I'd keep him on lead to start with so it's easy to reward him as you will be right beside him.

If he has an accident inside don't react at all. If you get annoyed he may learn to fear your reaction and avoid you if he needs to toilet or sneak off to do it in another room - the opposite of what you want. Dogs cant make the distinction between you being annoyed at him TOILETING, as opposed to toileting INDOORS. Justclean the area with an enzymatic cleaner to remove any trace of smell that might attract him back to the spot.

You may be lucky and find he is already trained.