Non-uniform acquisition to fixed sample rate
[WARNING, RUDE OPINION AHEAD]  Engine people often record data in a speed-invariant fashion using angular sampling. I have been working in that domain for a while, and I bear with you. I have been testing the performance of $0.1$ CA sensors, most of them doing some weird and undocumented interpolation. I also have tested $6$ CA sensors, at the other end of the camshaft.
My opinion so far is that they don't match well, for different reasons,
including the acyclic behavior of an engine:

some angular devices are crappy,

the analog filtering (if any) in the acquisition chain is not speed-dependent,

the speed cannot be assumed constant within a cycle, and even within a stroke.
And the measurements can be quite uneven at both ends of a camshaft, indicating that in between, at each cylinder, depending on the engine organisation, you might have various effects. This is all the more detrimental with noisy knock sensors :  their spec sheets are often imprecise, their calibration is often neglected, etc.


I have concluded that in a standard speed range (1000-4500 RPM), a precision below 0.2 CA is (often) meaningless. And at high speeds, 0.5 CA is doubtful.
So :

if you only have 0.1 CA data, do the simplest interpolation that copes with the processing you need. A simple LS interpolation (linear, splines) could do the work
if you have access to the angular timing for raw files, get rid of the spikes, and use it directly have a non-uniform sampling (but don't forget you only see it from one end of the shaft)
if you have data models, plug them into some super-resolution tool.
-if none of the above, well...

I'd suggest a track anyway, that I did not push to the end (so be careful): try to bound or to &quot;probabilize&quot; uncertainties: speed variation, quantization, filtering, etc. From the given measure, make a fuzzy measurement, ie a simulated multivariate object, that will go through further processing, which can give you a rough approximation of uncertainties pertaining to subsequent processing.