Halogens are obsolete, and forget HID.
There's a large assortment of replacement LEDs at Ebay for auto headlights.
I have experience with 850's, and now a 940.

The bad news:
*There are many bogus ads at Ebay, one Ebay seller claimed a 488 watt LED headlight, which is total BS. Some sellers feature even more crazy claims.

* LED specs given are often fradulent, missing key details such as current draw per lamp. Many seller Lumen output claims are not to be taken seriously.

*Some LEDs may not fit in the available space in the headlight housing.

*The Bulb out sensor can be an issue with some LED headlights.

* some LED's have physically bulky drivers that may make installation
difficult or impossible.

* Heat is the enemy of high power LEDs, many include fans, the brighter ones
draw more current and make more heat and could result in shorter life.

*Some LEDs I tried had current limiting @ 2 amps or 28 watts
that's a tactic to manage heat and service life.
So the guarantee is important, "So many years" Get a screenshot.

You can go to Ebay and search for "2000 Volvo 240 LED headlight"
providing the vendor has free returns
(USA vendor,Not going back to China)
you should be good.
Get a screen shot of the vendor return policy that there are "free returns".
This is your ticket to try the LEDs. If they don't work then it's on the seller. Ebay has a guarantee if the product doesn't fit as well.

The performance varies widely between different LEDs.
Filament bulbs are no match for LED lighting once you find the right package.
You'll be happy with superior vision at night especially on dark wet roads.

LED prices have dropped way down so it's not a budget breaker to fiddle with
LED headlights. There's new offerings every month.
Check Amazon and Walmart to compare prices with any specific LED.
It pays to shop around.

I'm having good luck with Lasfit dual beam LEDs in my 940 after 14 months,
and they're on all the time for DRL / daytime running lights.
https://www.ebay.com/itm/323366411729
2x Lasfit LCplus 9003 H4 LED Headlight Bulbs Kit High-Low Beam 50W 6000K White

Report back with your results to help other 240 drivers that want better headlights.

Cheers, Bill