The RAND report doesn't paint a pretty picture, but I think it's worth considering the other side of the coin. The authors of the paper on the EFP BGs dont seem to totally agree in their introduction (page 6):
"Finally, even though Russian forces positioned near the Baltic countries dwarf NATO forces in the Baltic countries, the military utility of the battlegroups is greater than the tripwire moniker might imply. Contrary to early assessments that Russia could take local national capitals in a matter of days, sundry geographical and logistical constraints would hamper any large-scale attempt at territorial conquest."
Now, I haven't yet read in entirety the papers they've cited in the footnote (which names the RAND report as well), but consider the following from Conventional Deterrance and Landpower in Northeastern Europe (2019):
1. "Chapter 1 begins by assessing Russian intentions. Since intentions are hard to divine, it instead offers two plausible ways to think about Russia’s goals and motivations: 1) Russia is a revisionist actor, motivated by imperial ambitions; and, 2) Russia is a defensive actor, motivated by fear and insecurity. Both viewpoints are consistent with Russia’s recent behavior, but they yield contradictory strategic prescriptions. The United States needs a robust deterrence posture to stop a revisionist Russia, but such measures will provoke a defensive Russia. Conversely, the United States should try to assure a defensive Russia, but a revisionist Russia will perceive assurances as a signal of weakness. Without definitive intelligence on Russian intentions, the U.S. Army must thread the needle between two contrasting deterrent postures"
Committing the amount of equipment and manpower that the RAND report calls for would certainly antagonize Russia, and I can't imagine a way to justify that within the parameters of the 1997 NATO-Russia Founding Act that prevents us from permanently stationing troops there.
2. "In all four cases, full territorial conquest appears improbable. This is especially true of Poland, as Russia would have to traverse Baltic and Belarusian territories to invade Polish territory. The Baltic States are more vulnerable, but Estonian, Latvian, and Lithuanian defense experts are more concerned about a limited incursion aimed at grabbing small portions of their territory as a test of NATO’s resolve."
Russia certainly does not want to invoke an Article 5 response, so I truly doubt we'd see a full scale invasion of Latvia. Rather, I bet it would be more similar to Crimea/Donetsk, where little green men would attempt to seize Russian majority areas.
Full report in PDF here:
https://publications.armywarcollege.edu/pubs/3686.pdf