Tower Speakers Close to Back Wall

I need some advice on what types of speakers to consider for an upgrade.  The speakers will be in a combination living room/dining room that is 21’W x 24’deep with a cathedral ceiling that is 14’ high.  The listening position is a sofa that is 12’ from the front wall.  The speakers will be be positioned within 24” of the front wall, which is mostly windows.  Due to furniture constraints, the speakers cannot be put out much farther into the room.

My current system is simple.  I have a Roon server elsewhere in the house.  I have a Matrix Mini 3 Plus as a Roon Endpoint/DAC connected to a Rotel 1570 Integrated amp which is connected to a pair of Golden Ear Triton 5 speakers.  I also have a subwoofer. 

I have owned several different sets of tower speaker over the years.  Those speakers have had either down facing, side facing or front firing bass ports.  The wall behind the speakers has windows or window treatments, depending upon time of day.   There is also a metal radiator than can rattle along the entire wall.  I figured that the variety of stuff on the wall behind the speakers combined with the minimal distance to the wall would result in acoustic issues with speakers that have back firing speakers.

I would like to spend less than $4000 to upgrade the speakers whether they are new or used.  I would consider another amplifier as part of the upgrade if I think that it is necessary, but I would prefer not to spend the money.  My questions are whether I should consider back ported speakers or if I should stick to either front ported or acoustic suspension speakers due to the limited amount of space that I have behind the speakers.  I look forward to hearing your suggestions.