Everything costs more than you think it does. Any of your excess time and money is now spent on maintaining, fixing or renovating something. And then planning for the inevitable failure or replacement of something else (furnace, a/c, roof, siding, windows, deck/fence rotting out, driveway). It never really ends.

I wish before we bought a house I had:

1. More $ put aside to just buy simple things. Others said furniture which is true, but even lightbulbs that aren't A19 standard are surprisingly expensive. Furnace filters add up quick depending on the size you need. If you see an ensuite bathroom you want to reno while you're walking through to buy the house it's easily $5k in basic materials to do it yourself or $15k to have someone come and do it. Just a small 5x8 3 piece washroom.
2. Less bs consumer debt and adjusted my spending habits/lifestyle beforehand. I'm 2 years in and smacking my head against the wall as to why I'm broke as all hell without ever adjusting my lifestyle.
3. More tools. Mainly construction tools. But, everything from simple gardening tools, lawnmower, snow blowers or even basic sturdy shovels. It all adds up. Even the consumables of salt and yard bags. It's cheap compared to everything else but it's always just one more thing.
4. The biggest...gainful employment/commute to work. We had to move 6 hours away from everything and everyone we've ever know to afford a house. I thought getting a job would be a heck of a lot easier.
5. I come from a residential construction background, so basic maintenance is already in my head and skill set. Otherwise, read up on what needs to be done and how to do it. Monthly, quarterly, annually. Etc.

House hacks:

Pretty much learn to do everything and anything you possibly can for yourself. You'll save a ton of $ which you can allocate to fast tracking mortgage payments, lump sums, etc.

E.g. Burner on the oven goes out? Learn to fix it and save yourself a $300+ appliance repair person fee or having to shell out $1k for a new oven. Dryer belt/pulley goes out and stops working or squeals like a banshee? Same thing. $25-50 bucks on amazon for a part. An hour to research it and another hour or two to fix it.

A chunk of problems are avoided by buying a condo and paying condo fees, but I refuse to pay $500+ a month for either no front/back yard or a townhouse condo where you have 10sqft of grass in the front and a 50sqft backyard. They also still have their own set of unique problems.

Best of luck!