What is the best sling bag for my photographic equipment?

I have a Fuji X-T4 next to the 18-55mm lens (with the hood), plus the loose 50-140mm lens (with the hood turned) and a small Meike MK320 flash. In addition to batteries, cables, tissues, a spare mask and some other small accessories.
I am looking for a sling bag to carry every day. I have the 6-liter Peak Design and the gear fits, but too tight. I think that the Peak Design 10 liters is going to be too big and Peak Design does not make bags between 6 and 10 liters.

Does anyone recommend a sling bag for that photographic equipment? It may be from other brands, but I want it to be black and discreet.

I like the Think Tank sling bags... I don't have those lenses, so not sure about sizes, but imagine the ThinkTank MindShift Photocross 10 would fit what you describe:

https://www.thinktankphoto.com/collections/photocross-sling-bags

I would suggest checking out mountainsmith descent sling.  Not sure if it would be discreet enough, but I have the larger of the two sizes and really like it.  Both have expandable zippers.  The small one can go from 6 to 8 liters and the larger one goes from 11 to 14 when they are each expanded.  It’s very similar to suitcase/luggage that has zipper expansion.

Big one fits my x-t4 w/100-400 mounted and X-T2 w/16-55, a filter pouch, straps, batteries, 1.4 ext., macro extension tube, a prime (usually the 56 1.2).  Expand it and I can pile in more stuff.  The large one has a attachment strap/point for attaching even more things, or allowing the ability to slide the leg of smaller/travel tripod in to carry as well.

I also had the larger 10L peak design sling and got rid of it because it was too big/similar to the descent sling when I wanted to go ‘smaller’.

The thinktank urban access slings look really nice.  I think the size 8 would correspond to 8 liters?

Have to keep reminding myself, I don’t need more bags, I don’t need more bags.

I have a Lowepro and I'mvery satisfied

Don’t discount buying a camera bag “insert” and putting it into the bag of your choice. For my gear I just bought a Messenger bag and added some padding and separators.

I would like to know if the 50-140mm f2.8 lens fits upright in the Think Tank Urban Access 8 bag
Thanks !!!