I think the days of strict spacing rules in style guides worked well when the screen sizes and resolutions on devices were not as diverse as it is today. But with responsive web design the main motivations of setting up design systems, it is more advantageous to have design system rules based on proportions and ratios rather than absolute values, because you can’t scale or adapt to different displays and devices very well that way.
But it is also worth taking into consideration whether you are looking at spacing as an isolated instance of design system/style guide rules or if there are other aspects that are also set in stone. I think you’ll find that strict spacing rules will have an impact on other parts of the design system as well, so I would expect that if you set very specific rules for spacing then you will also need specific rules for UI component dimensions so that the spacing rules will work well.
When you say that your “company has multiple in house applications in development”, I assume that these are internal facing applications that are probably deployed within a standard operating environment (e.g. company desktop machines and laptops that are similar enough), so it could make sense to use more strict rules when there are less variables to consider and deal with.
As usual, it is also important to consider a design system/style guide as a product or service, so it is good practice to ensure that the product or service is fit for purpose for the users (i.e. the designers and developers).