Proposed Continuing Resolution gives the President power to cut Smithsonian Budget by an unrestricted amount

https://rules.house.gov/sites/evo-subsites/rules.house.gov/files/documents/crfull_xml.pdf

Page 14 gives the President the ability to sequester funds and goes on to list the Smithsonian by name. This will probably allow the executive to RIF the Smithsonian, possibly affecting museum access and definitely affecting museum and research functions.

Normally only Congress and the Smithsonian Board of Regents has control over the purse of the Smithsonian.