Very "heavy" front mech shift - any ideas?

The front derailleur on my Arkose is really heavy to shift. The whole set up is a bit of a mish mash of what I had available - 105 brifters (10 speed not sure of the gen) and a Sora front mech. The inner is a brand new Shimano optislick thing, outer is new Jagwire.

The mech moves freely, I've just installed a new inner cable, taking care to ensure it wasn't tangled around any other cable in the frame (F&RD and rear brake cables all follow the same internal routing).

The rear mech (same combo) is very light to shift so not sure where to look. And for comparison the FD on my Storck (Ultegra 6800 throughout) is just lovely.

Any ideas?

What model# is the shifters and FD?

I damaged my FD (r8000) and so had to use a spare 5800 I had in my parts bin. I assume that because of the change in FD design between the two groupset iterations, the FD was so hard to upshift with my r8000 shifters.

Any tight bends in the outer cable? Can even be a small kink where the cable goes into the shifter

I "think" the shifters are 5700 and the FD is R3000.

Don't think so - it all looks pretty smooth.

Is the cable run exactly as it should be? Very small deviations (one side of clamp both rather than the other for example) can have a big impact on leverage force required

Well a bit of Googling suggested that a possible cause is the cable being too tight - I slackened it off slightly and it has improved, albeit only a bit.

Do you have photos of the routing. Particularly where it attaches to the mech.

it looks like the there's a little conversion plate within the r3000 front mech that has to be switched depending on the cable run.
link to the installation guide here - https://si.shimano.com/en/pdfs/dm/RBFD001/DM-RBFD001-01-ENG.pdf

I think that is a different mech from mine - maybe I was wrong with the number. Mine just has the normal bolt with a washer and a groove for the cable in the arm.

I can take one or two, no problem.

Sora only just got up to 9-speed with the latest generation so earlier ones definitely won't be compatible with 10 speed shifters. That setup might work after a fashion, but it might also explain a heavy shifting feel.

They are 9 speed gen Sora, but it’s the front shifter anyway so only 2 speed - hard to believe that could be the problem unless there is a pull ratio difference?

The rear - 9 speed mech on 10 speed cassette and shifters - is absolutely fine.

Here's a picture as requested. Sorry it took so long, I was away and then forgot.

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