Is There Any Way To Update A Mod Without Remaking It?

Which mods, and what exactly do you mean no longer work? Did you make sure mods were enabled after patching and clearing your localthumbcache? And did you check for any updates to them or alternatives?
And if you know what you are doing, yes, you can update mods without remaking them. If they were already abandoned though and last updated many years ago (like Nix's mods), then it's always better to make them from scratch and just copy certain things over because of SimData changes and more.

If they were a simple mod (like no autonomous, increasers/decreasers, etc.) then it's just a matter of following this tutorial to compare the changes and make adjustments.
If it's a custom mod similar to Slice of Life for example, etc., then you need to be aware of what changed in the patches in order to fix what broke. Unfortunately there's no universal list, and the CoL patch was massive in the amount of changes that occurred. You can use Tuning Error Notifier (TEN) to at least get a starting list of what broke in the mod (recommended to do this without any other mods in the folder to not crowd the list, it seems to cutoff at a certain amount), then it's just a matter of looking up EA files to see what changed and fixing the formats.

For example, in the patch SituationJob had some changes to the ranges, and the error looks similar to this:


The key word here is "value_range", you would open a search program like DocFetcher and then narrow the search to the TYPE it mentioned (in this case SituationJob), and lookup "value_range", you will get results to compare to.
It used to look like this:
<U n="value_range">
<T n="lower_bound">75</T>
<T n="upper_bound">100</T>
</U>

Now it looks like this:
<V n="value_type" t="int_range">
<U n="int_range">
<U n="value_range">
<T n="lower_bound">75</T>
<T n="upper_bound">100</T>
</U>
</U>
</V>

So in the file(s) that are spitting this error, you need to go in and fix the format of the value_ranges in the SituationJob(s) to match the new one. The majority, if not all, errors should follow similar concepts to this, unless something more internal changed or the mod barely worked beforehand because of other errors, but that should at least give you a starting point.