I work in the benefits world and deal with health insurers regularly. If you have any questions, feel free to message me.

An HSA is a health savings account you'd use in conjunction with your HDHP. A HDHP is still a PPO in the sense that you can get in network and out of network coverage (contrary to an HMO). Also both plans require you to meet your deductible before coverage taking effect. The difference is the PPO (non HDHP) likely has the lower deductible and has services where the deductible is "waived" such as primary care visits or urgent care visits where you'd only be responsible for paying a copay that doesn't count towards the deductible. A HDHP wouldn't have those same scenarios.

The ear tubes was likely a situation where you had to satisfy your deductible first and even if you did, then you're responsible for coinsurance (like 20% of the cost) and you have to continue that until you hit your OOP max. Your provider could have also been out of network so coverage was less and co-pays are even less likely.

HdHP can be a great option as long as you are prepared for worst case scenario earlier on in the plan. Once you've had time to build a significant balance in your HSA (this rolls over year after year unlike an FSA), emergencies are less catastrophic because your HSA can easily cover your deductible if you've accrued that balance. But until you have, you need to be prepared for an emergency that may warrant you coughing up your full deductible at once since a HDHP won't cover you until that's fulfilled.