You might prefer a LDO regulator with decent HF PSRR.
These are a thing, now. Their whole purpose is to clean
up switchers for fussy loads.
For light loads you might LC-filter, but anything you add
in series will degrade load regulation and load-step may
be compromised - you'd have to ensure that your close-in
filtering can supply the 200mA for the 10us at an acceptable
voltage sag across the pulse duration. If I called it 1V sag,
that would be a C=2A*10E-6s/1V or 20uF? That's not
terrible. An inductor with a sub-ohm DC resistance ought
to not bother DC level "too terribly".
You'd have to check out the box between fSW of the switcher
(which you must reject to the tune of 95%, so filter tau at least
2X, maybe 3X switcher period) and the rep rate of the pulses,
which can't be allowed to "staircase" the local supply downward,
meaning filter tau must be similarly a 1/2 - 1/3 fraction of that
rate. If you've got a 100kHz switcher and a 1kHz pulse rep rate,
you might just be able to fit an acceptable corner freq in there
at 10kHz or so. 100kHz switcher and 10kHz rep rate, that's
liable to bother one end or the other.