You can use the gtsave function and save as a .png and it will output. For example, here is a plot that I generated with the following code:
{r mOS Table Generation, fig.dim=c(6,8)}
mostable <- mosdf %>%
ungroup %>%
select(-Dose) %>%
gt() %>%
tab_header(title = "Median Overall Survival (mOS)", subtitle = md("*Subjects Treated from REDACTED*")) %>%
tab_spanner(
label = "95% Confidence Interval",
columns = c(5:6)) %>%
cols_align(align = "center") %>%
tab_style(cell_text(weight = "bold"),
locations = list(cells_title(groups = c("title", "subtitle")),
cells_column_spanners(spanners = everything()),
cells_column_labels(columns = c(1:4)))) %>%
tab_style(cell_text(style = "italic"),
locations = cells_row_groups(groups = everything()))
setwd(output)
gtsave(mostable, "mostable.png", vwidth = 1500, vheight = 1000)
Here is how it looks the R Markdown when knitted to Word:

Note, even though I have the dimension statement in the chunk code, gtsave is dependent on webshot, so the vwidth and vheight control the size of the output to the working directory. Most of the time the output size is fine, but I am still working through how to change the output size. Most of the time I just manually do it, but prefer to not have to update the output. I am going to ask another question, so I will link if there is a solution.