I haven't used my PRO-164 for 2 years. We moved and I haven't been as active chasing aircraft. Last time I used them was from Marathon Florida in April 2022.
I have been listening with one of them the past few days since you decided to get one. They are fantastic on VHF and UHF air. Nice clear audio. Very good reception. The stock antenna that came with them performs just fine, but the stock antenna that comes with the Uniden handheld scanners are a bit better. I would suggest using a telescopic antenna extended to about 21 inches. They are pretty cheap on Amazon. One for $5.99 two for $7.99 US.
POBADY BNC Male Connector Telescopic Antenna 7 Sections VHF UHF 68.5cm/27IN Telescopic BNC Plug Antenna for CB Radio Police Scanner Ham Radio Two Way Radio Mobile Scanner Wireless Microphone
https://a.co/d/8txbrO2
I use a VHF transceiver rubber duck antenna made by Yaesu on mine. Yaesu YHA-74. They are about $25 US. I have one for each PRO-164. A similar one came with my Yaesu VHF air transceiver. They work well receiving on UHF as well. They even work well receiving VHF high band frequencies including VHF marine.