These fares book into "P" and are marketed as "business lite" by Qatar and displayed either as such or as "business (P)" on the website when booking through the QR website.
When booking through other portals, watch out for "P".
When in doubt or the booking engine you use doesn't display fare codes, use ITA matrix to check pricing for different fare classes before booking.
There usually is a substantial price difference between the 'lite' and 'classic' fares.
See the fare structure here: https://www.qatarairways.com/tradepo...eFamilies.html

Lounge access is still granted upon your connecting flight class of service,yes You will still be able to visit the Al-Safwa lounge with a ticket where one leg is in First class, no matter if it's regional F or longhaul F.