Starfield is the latest in a long line of games to commit the cardinal but common sin of not making NPCs match the walking speed of the player. It sounds like a minor quibble, but it crops up so often that it's driving me loopy, resulting in me trotting ahead of NPCs while screaming at them as I completely lose the plot.
Every single person in the galaxy seems to have had a meeting where they decided to walk just fast enough so that they outpace me when I'm walking, but slow enough so that I end up ahead of them when I'm jogging. Regardless of whether I'm using a mouse and keyboard or a controller, there is no way to match their pace.
Since a lot of quests require you to follow an NPC, you'll find yourself stopping and starting constantly as you try to get to your destination. Some (but not all) NPCs will pick up the pace a bit if you run far enough ahead of them, but you'll still have to wait for them to catch up and, crucially, you won't actually have a quest marker showing you where they are taking you.
It's kinda wild that this issue is still cropping up in 2023. It's present in Bethesda's previous games, and the studio is far from the only perpetrator of this heinous crime. And there's seemingly no logic behind it. There's an argument that it allows players who get distracted to easily catch up with an NPC, but there are already better solutions to this problem, like NPCs waiting if the player falls too far behind, or quest markers that show players where to find the NPC if they lose sight of them. Indeed, Starfield already employs the latter, making the NPC walking speed even more ridiculous.
Like so many of the recurring issues with Bethesda games, it's been left up to modders to fix this, which they've done with some simple command line mods. These are easy to use, but will require you to make a tweak to the StarfieldCustom.ini file.
Simple Faster Walk
This mod from Somberx increases the player walking speed by 50% so you can keep up with NPCs while walking. After downloading and extracting the ESP to your Starfield data folder, all you need to do is add a line to the StarfieldCustom.ini file. If you don't see this file in the Documents\My Games\Starfield folder you can simply make one.
If you play in third person a lot, you might prefer to use the alternative ESP that increases your speed by 30% instead. This means you'll be a bit slower, but the third-person animation doesn't look as weird.
Better Movement Speed
JamesbonDB's mod takes a different approach. Instead of increasing the player's speed, it decreases it, so you won't immediately just leg it past NPCs while jogging. It also includes a few additional features.
Mouse sensitivity has been optimised to match your display ratio, and this feature also disables mouse acceleration. If you're using a controller, the mod also makes some tweaks to make aiming more precise and increases controller response time. Installation is a bit more involved, however, and you'll need to use console commands as well as adding new lines to the StarfieldCustom.ini file.
This mod isn't specifically designed to help you match the pace of NPCs, it's broader than that, but if you find the default settings make you too slow when following NPCs, you can make tweaks to the file you've downloaded to tailor the speed reduction to your needs.
Conveniently, both Simple Faster Walk and Better Movement Speed can be used together. It's slightly annoying that we need to turn to modders to solve such a basic problem, but if it's been bugging you as much as it's been bugging me, at least you now have a solution.