Different lenses have different behaviours, but as a rule of thumb: if you need maximum sharpness in the center but don't care about corners (for example you are shooting a portrait with shallow DoF), set your aperture to one step higher than lowest available. If you need sharpness across whole frame (typical landscape) start with f/8 and adjust as necessary - some lenses be sharpest at f/5.6, other will need stepping down to f/11.

While higher f-numbers increase depth of field and reduce optical aberrations in extremes of optical circle (corners and edges), they also introduce diffraction effects across whole frame leading to decrease in overall sharpness. I recommend getting a tripod and shooting the same scene few times with different settings to learn how your lens behaves at different apertures.

On lenses with small image circles (covering only crop sensor size) diffraction effects will kick in faster, this is why @xiota recommended f/5.6 as starting point for you. On the other side of a spectrum are medium and large format cameras - those will often use f/16 or f/32 and will still have good sharpness.

Additional point: getting exposure right and good post-processing is more important than overall sharpness. There are already great answers in your linked previous question. Getting a tripod and better quality prime lens will help (for landscape you can use older, cheaper manual focus lenses - that tree or mountain will not run away as you spend few seconds setting the focus). Another step is using tripod and ND filter for longer exposure times to get that nice, smooth vegetation or water surface while static objects stay razor sharp.

To answer your question in more simple terms: In general it is not a good practice to use a low aperture for landscapes, but is it is better than underexposing or getting a camera shake from long exposure time.