My setup is similar. I have jbls with DAC Amp and sit stand desk and monitor and what not. I would recommend moving things in a way that the cables can flow together. I personally like zip ties and adhesive backed tie downs. Once the start and end of cables are place you can unplugthem, coil them, zip em and attach them to the bottom of the desk. You can buy short cables that suit your specific layout too if some are to big. You can route the cables up the leg, coil them under the desk.

For the monitor arm, you can create a slack loop after the point of congestion. First fully extend the monitor taking up all the slack. Zip tie the cable as close to the monitor and then zip tie it close to the base when you put the monitor back from full extension it will have a loop or bit of slack for moving around

Zip Tie Adhesive-Backed Mounts 100 Pack by Nova Supply. Professional-Grade, UV Black Cable Tie Bases: 1.1 x 1.1. Screw-Hole Anchor Point Provides Optimal Strength for Long-Term Durability & Use https://www.amazon.com/dp/B06XNBS6TG/ref=cm_sw_r_cp_apa_i_uleaBbT5ZWY8M

You can search for zip tie mounts and find ones big enough for Velcro:

Zip Tie Adhesive-Backed Mounts 100 Pack by Nova Supply. Professional-Grade, UV Black Cable Tie Bases: 1.1 x 1.1. Screw-Hole Anchor Point Provides Optimal Strength for Long-Term Durability & Use https://www.amazon.com/dp/B06XNBS6TG/ref=cm_sw_r_cp_api_i_IbwFEbN6F0082

50 Pcs Black Cable Tie Base Saddle Type Mount Wire Holder, Cable Zip Ties with Self-Locking 6 Inch & 0.145 Inch,#8 x 0.6 Inch Deep Thread Pan Head Screws Black https://www.amazon.com/dp/B07J4H65DK/ref=cm_sw_r_cp_api_i_ncwFEbX3QJY5K