Missing Aesthetics Geometry

I am looking to create a map using the following dataset:

with the shapefile of:

Here is my R code:

library("tidyverse")
library("dplyr")
library("sf")
library("ggplot2")
library("tmap")
library("tmaptools")
library("RColorBrewer")


data = readr::read_csv("C:/Users/amanm/Desktop/annualincomedata2.csv")


localauthorities2 <- read_sf("C:/Users/amanm/Desktop/localauthorities2.dbf")

mymap <- merge(data,localauthorities2)

ggplot(mymap) + geom_sf(aes(fill = Total)) + scale_fill_viridis_c()

Upon running the code I am given an error code:

> ggplot(mymap) + geom_sf(aes(fill = Total)) + scale_fill_viridis_c()
Error in `check_required_aesthetics()`:
! stat_sf requires the following missing aesthetics: geometry
Run `rlang::last_error()` to see where the error occurred.

Any advice would be helpful. Thanks