Can I connect my Mac mini to a Smart TV Set

Yes.

Traditionally Mac mini’s were used as home theatre systems before Apple released the Apple TV.

I have my 2018 Mac mini connected to a Philips 65PUS6703 running at 4K 60Hz through a Denon AVRX-2400H AV receiver.

One thing you will want to do however is put the TV (and AVR if you use one) into Monitor/PC/Computer mode so that it disables the ‘enhancements’ they often apply such as motion smoothing or colour/edge enhancement.

Yes. Use a HDMI cable.

Depending on the make of TV, there are third party apps that will let you connect over your Wi-Fi.

Also you can connect through Apple TV.