You mention your TT with the Ortofon M2 Blue cartridge and the Schitt Mani 2. All good choices at the price points, but you don’t mention what amp or integrated you have and how much power it has, or whether it is rated well for 4 Ohm speakers or only good for those 6 Ohm to 8 Ohm. That does matter.
As noted by others, in a large room (you didn’t say how large) small bookshelf speakers without a subwoofer are well, going to sound "small". And forcing them to play louder than designed will cause distortion, clipping, or even some damage to them.
If you are looking for a "party speaker" you likely won’t go wrong with Klipsch RP-600M (either the old version that you might find "new" for a good price) or the newer MK II version. Those are around $489 at Amazon right now!
I have the Wharfedale Diamond 12.2 (got an open box deal at Crutchfield a few years ago) in my den (10’ x 10’ roughly) serving as main left and right speakers in a 5.1 surround sound system powered by an old Denon AVR. They do the job, but I rarely turn them up much above 90dB. I have them paired with a cheap Klipsch subwoofer and it really helps significantly to round out the sound so they don’t sound "thin".
I don’t think they are "bright" at all, but then I’m 67 and my hearing rolls off at 14kHz.
Note these are rear ported. I think the RP-600M are also rear ported, so that might be a deciding factor depending how close to the wall you want them to be. Closer will enhance bass but too close will make it muddy.
In my living room (13’ x 25’), I recently bought some front ported Triangle BR-04 (the larger brother to the old BR-03) to use for a while until my larger floor standers can be refurbished.
These speakers are a step up I think in audio quality, but I wouldn’t consider them "party speakers". I have them pulled well into the room and sit on a couch only about 10’ away from them.
If "loud" is your main concern and not audio quality, think about those Klipsch, price some Zu speakers too, known for their "lively" sound and easy to drive.
At the end of the day, you might be better served for loud sound by some Polk or Fluance floorstanders that have more radiating surface area.
Note in my computer room, I have the ELAC Debut 2.0 B6.2. Those are not very good in my opinion. They are large bookshelf speakers but have little bass. They are "good" at a $250 price point which is what I paid for them from Crutchfield "open box".
Once my floor standing speakers are refurbished, I plan on replacing the ELACs with the Triangles and selling the ELACs at a yard sale.
Note that many reviewers hated the ELAC B6.2, but liked the smaller B5.2, saying it had better bass. But even so, they are not the ticket for filling a large space with sound.
Good luck.
