Can I watch Apple TV plus on my tv thru my iPhone 11?

You can if you have an AirPlay enabled TV (e.g. select LG models).

I’m pretty sure HDMI adapters are not supported for this service.

Non-AirPlay wireless casting options (Chromecast etc.) are not supported for this service.

You can also watch Apple TV+ on your TV using the Apple TV set-top box (3rd generation or later), compatible Roku device or compatible Amazon Fire TV device.

God forbid they allow that. Apparently Apple thinks that the only TVs on the planet are 2018/19 Samsung TVs.