Yes, slow slip events, or alternatively episodic tremor and slip (ETS), and a variety of other "aseismic" processes represent long-duration versions of strain release that occur on a variety of subduction zones (Cascadia included) either completely independent of traditional seismic events or in concert (e.g., afterslip) with them. Of relevance though, they are explicitly not earthquakes in the typical definition (i.e., they are aseismic) and as the focus of the question is "do small magnitude earthquakes impact the probability of large magnitude earthquakes?", slow-slip / tremor discussions gets a bit into the weeds (so me leaving them out was a conscious choice).

If we consider equivalent magnitudes, most observed slow-slip or ETS events are still kind of in the ball park of "small events" , i.e., mid 5s to 6s, but some do release equivalent magnitudes of strain as a Mw 8+ if you "sum up" the total moment of the event over the days, weeks, months, etc. (e.g., Schwartz & Rokosky, 2007). Perhaps more importantly, the extent to which patches of subduction zones which experience these various aseismic type of slow/quiet/silent slip (1) restrict which patches fail seismically, (2) influence the balance between seismic slip vs aseismic afterslip in the patches that do fail at least in part seismically, or (3) themselves can rupture seismically given the right conditions are all very active areas of research, largely without clear answers, or at least answers that are easily generalized to all subduction zones (e.g., Rolandone et al., 2018, Mallick et al., 2021, Zhao et al., 2022, etc.). Thus, while it is reasonable to consider that slow slip and similar aseismic processes influence the style of seismic strain release, how they do so (both mechanistically but also in terms of actual event temporal and spatial statistics) is a large open question.