If you want to personalise you're brew, without the precise temperature and faff of all-grain, then you certainly can. You will have to boil, though (at least to some extent).
The big step with all-grain brewing is mashing the grains, to convert the starches in the malt to sugars. However, there are lots of malts that do not need mashing. As a rule of thumb, anything with "crystal" or "cara" in the name does not need to go through a complicated mashing process. With these, the way they are malted means that the starch conversion happens during the malting process. You can therefore use them simply by "steeping" the crushed grains in hot water to release the flavours and fermentables.
This means that it is possible to make personalised recipes by combining malt extract, steeped grains, and hops. Unlike extract kits, you will need to boil - if only to release the bittering factors from the hops. But, in my experience, this can be very brief (not like the protracted, vigorous boils most all-grain brewers employ)
A quick way into this would be to buy a kit consisting of extract, hops and steeped grains. Perhaps something like this:
https://www.themaltmiller.co.uk/product/doombar-mini-mash/
Here, you don't need a huge pan because the malt extract isn't boiled at all, just the additional grains. With this kit there is only crystal malt and roasted barley. Neither of these need actual mashing, so although Malt Miller call this a "mini-mash" it really isn't - the grains only need hot steeping and the time/temperature isn't critical at all which makes life easy.
Once you get the hang of it, there are loads of "cara" or "crystal" grains (as well as dark-roasted) that you can play with to adapt recipes, or make up your own - without a lot of kit or knowledge.
WARNING - you won't stop here though - this "soft" brewing will surely lead into the "hard" stuff of all-grain!