you could do either.

if you want to gel stain, you will have to remove the door from the hinges, and strip off all of the old top coat/stain. sand. once you are at bare wood, stain your new shade.

Some will say you could just do a darker gel coat over what you have. (you still have to sand off the original top coat. that is what has yellowed w/age. oil base clear coats amber w/time) If you just do that, you may end up w/a blotchy type of finish where you have dark and lighter, original stain colors. it will look like crap. I do a lot of wood refinishing. I know what works and what doesn't.

And, if you want to stain them much darker (like a java or espresso) , then you might as well paint them. They're pine doors, not solid oak or mahogany. not a big deal in my book.

painting them will be so much easier than staining them (properly). If you don't believe, practice on one door that you don't see all the time (like upstairs in the corner or something) Or practice on the INSIDE of one of the doors.

here's a color that somewhat matches your gray floor.

change out your old knobs to black while youre at it

a lighter gray color.

or go w/a black door, white trim

you could also do lever handles. This after is similar to your wall color. they did a black

showing how painting the doors in hallway white brightens up everything.

Sorry but IMO they no longer work with the floor so unless you stain them really dark brown I would just paint them the same as the trim BTW you will need to prime first with a shellac primer to keep the resin from bleeding through

Number them on the bottom edge and send them out to be Pro sealed and spray-painted. Match the trim color, or a medium-brown that's found in your pretty floor.

I don’t get a good take on what your style preference is but you may consider Ben Moore “ebony” ( off black) & changing the door knobs to lever style in the metal of your choice for a more sleek, updated look.

Those are great looking doors! If these were mine, I would take the time to strip them down and restain them. Every house these days has cheap hollow core doors that have to be painted because that's all you can do with them. If you paint your doors, they will look like the same cheap hollow core door. Because your doors are solid wood, they are an architectural feature. I would also ramp up the style factor by replacing the hinges and knob with something more upscale and current.

We had the same and we painted. Make sure to use a stain blocking primer first so the orange doesn’t bleed through.

I have same doors but there is 18 of them and seems huge task although I do want to change them as so dated now. Any ideas how long this would take me?

Also I love your floor, can I ask the colour and is it engineered wood? I changing some of my flooring and been looking and getting samples for ages but I just not falling in love with any.

I have the same doors and would not even think about painting them.

That is a classic style and a classic color. Very similar to doors in Mount Vernon, particularly the West Parlor door. Scroll down the page at the link:

https://www.mountvernon.org/library/digitalhistory/digital-encyclopedia/article/interior-architectural-details/#eastdoorway

https://www.oldhouseonline.com/interiors-and-decor/guide-old-doors/