Jumping in here because I went through this exact same headache last year. Too much money went into the body and there was basically no cash left for glass. Honestly... trying to make the Panasonic LUMIX S 20-60mm f/3.5-5.6 work for sports was a total letdown. Unfortunately, you just cant get close enough from the sidelines and my kids looked like tiny ants in every shot. There were constant issues with the focus speed too when they were running fast. Scouring the used markets for weeks was the only way I survived. Eventually found a used Panasonic LUMIX S 24-105mm f/4 Macro O.I.S. which was better for travel, but still kinda struggled at the long end for soccer. Hunting down a used Panasonic LUMIX S 70-300mm f/4.5-5.6 MACRO O.I.S. for around 700 bucks might be your only real shot for those games. It's tough when the budget doesn't match the goal, ngl.

Jumping in here because I've been really satisfied with the Panasonic Lumix S 24-105mm f/4 Macro O.I.S. for exactly what you're doing. It's a solid piece of glass that stays on my camera 90% of the time. While 105mm is a bit short for the far end of a soccer field, it's basically the best middle-ground you'll find for under 700 bucks if you buy used. A couple quick tips for the S5II setup:

• Map the APS-C Crop function to a custom button. This gives you a 1.5x reach boost, making that 105mm act like a 157mm lens.
• Shop the used market. You can find copies in great condition for around 600 or 650 pretty easily. It works well for travel because the stabilization is incredible, so you wont need a tripod for most shots. No complaints from me on the image quality, it just works.

Ngl I am basically in the exact same spot right now. Spent way too much on the S5II body and now I am staring at my bank account wondering how to get good shots of my kids without going broke... it is a struggle for sure. I have been looking at two paths for that reliability:

• Sigma 28-70mm f/2.8 DG DN Contemporary: This is super compact and I am happy with how Sigma builds stuff, but the reach is kinda meh for soccer sideline shots.
• Panasonic Lumix S 28-200mm f/4-7.1 MACRO O.I.S.: This is the one I am eyeing for safety. The AF is usually more reliable when you stay native, plus that 200mm range actually gets you to the other side of the field. Just glad I am not the only one feeling lost with all these numbers tho... let us know what you end up with.

Ngl I am in the exact same boat and it has been driving me nuts for about a month now. I spent a huge chunk of my budget on the S5II body thinking the phase detect would solve everything for my kids games, but finding a zoom that actually has the reach and aperture I need for under 700 bucks is honestly proving impossible. It is so frustrating because you look at the technical specs of these lenses and anything with a decent constant aperture just blows past that budget immediately... I still havent found a single thing that works for me either. We are basically stuck in this weird limbo where the gear we want costs twice what we have left.

Can confirm this works. Did the same thing on mine and its been solid ever since.

I'd basically just stick with what Panasonic makes for their own system. Their mid-range zooms are decent options for travel since they arent too heavy. Sigma is the other big choice for L-mount and usually works well if you want something a bit more rugged for sports. Stick to those two and you wont have any issues staying under budget.