Do I need to confirm my entire itinerary for a 60-day tourist visa in Thailand?

When I booked my travel they only required confirmed reservation for my week in sandbox (Phuket). In the past people will book a day or a week or whatever, just for the paperwork. Book a reservation that allows cancellation if you need to book anything further than a week.

Just get the first few days booked and they are ok with that. It's now necessary for all landlords/hotels to register their guests on government website. So if you extend your visa, you need to be booked into somewhere before and after your extension. A day either side helps them and saves them having to call your landlord/hotel to check they have registered you. Loads of reasons for this...they need to know where you are at all times. They are not really tracking you or confining you to one place. They are just being cautious. When the tsunami hit Thailand years ago, they didn't know who was where and got hugely criticized by our governments for not "keeping tabs' on tourists. So, the system of registering guests has come out of that. This is often why you pay more money to stay at a place for a few nights. If you are staying a week, you get a discount as the property owner doesn't need to fill in the tm30 every day. Some Thai bungalow owners are not internet savvy and have to pop into immigration to register or fill out a form...who wants to do that for every customer every day. So, it is preferred but not essential that you stay on the island of choice for longer than 5 days rather than moving around all the time. Also it's cheaper for you. Course you can book and cancel on sites like Agoda but remember everyone is doing that so the prices on these easy to use booking sites are often much higher than you would pay at the door. Because the system is being abused so the costs go up. Book a few nights in Bangkok and then move on from there.

Thailand has got to change all of these regulations they are too hard on tourists and they'll keep tourists away until they start to relax and welcome tourists again

They act like they want the whole itinerary but they don't give a shit in reality. Just put down your first destination.

Got mine last week only showed a photo of agoda confirmation email for 5 days.

Immigration stamped me 60 days no probs 2 hours ago

I doubt they’d need confirmation for the whole 60 days for a TR visa, but some visa types do need confirmed bookings for the entire stay.

If you find a place on Agoda that is cancellable then you could always book that then cancel when you have your visa.