The party as a whole isn't made up solely of its current representation in Congress or Trump and his sycophants. Voters on the right overwhelmingly support Ukraine over Russia. Per an Economist poll, only 5% of Republicans support Russia over Ukraine, for example.
Link: https://docs.cdn.yougov.com/aa58ig9d3b/econTabReport.pdf
90% of all Republicans, including Trump supporters, believe that Putin is responsible for the war.
The majority of non-Trump Republicans (about 53% of the whole) support continued aid to Ukraine in the war, both financial and military.
40% of Trump Republicans support continued military aid to Ukraine, while 33% support continued financial assistance.
https://globalaffairs.org/research/public-opinion-survey/majority-non-trump-republicans-support-continued-aid-ukraine
A good summary of some of the 5%: https://accountability.gop/ukraine-quotes/
If you'd asserted that the GOP caucuses in Congress were all pro-Putin (as opposed to the entire party), the assertion still fails when presented with evidence to the contrary. A couple of examples:
A bill to expand sanctions on Russia and Belarus passed the House with almost unanimous support, including 202 Republicans:
https://www.congress.gov/bill/117th-congress/house-bill/7066/related-bills
A later version became law: https://www.congress.gov/bill/118th-congress/house-bill/5512
How does that become law with near unanimous support if the Rs are all pro-Putin? Wouldn't they be under orders to kill the bill?
A bill to sanction Putin's enablers in relation to the invasion of Ukraine was introduced by two Republicans:
https://www.congress.gov/bill/117th-congress/house-bill/7163/cosponsors
Additionally, many of the current and former Republicans who oppose Trump's 2024 run are probably unlikely to be pro-Putin, though support of Trump and support of Putin are two very different things, the claims to the contrary notwithstanding.
https://en.wikipedia.org/wiki/List_of_Republicans_who_oppose_the_Donald_Trump_2024_presidential_campaign