Looking for some suggestion

I have an integrated object. I removed 4 clusters and want to re-cluster . Below are the steps I ran, however, I am getting error while trying to run the FindAllMarkers

DefaultAssay(Integrated_object) <- "RNA"

cells_to_remove <- WhichCells(Integrated_object, idents = c("CLUSTER_6", "CLUSTER_9", "CLUSTER_10", "CLUSTER_11"))

##############
Integrated_object_Subset <- subset(Integrated_object, cells = setdiff(Cells(Integrated_object), cells_to_remove))
Integrated_object_Subset_list <- SplitObject(Integrated_object_Subset, split.by = "Sample")
Integrated_object_Subset_list <- lapply(X = Integrated_object_Subset_list, FUN = function(x) {
    x <- NormalizeData(x)
    x <- FindVariableFeatures(x, selection.method = "vst", nfeatures = 2000)
})
features <- SelectIntegrationFeatures(object.list =Integrated_object_Subset_list)
anchors <- FindIntegrationAnchors(object.list =Integrated_object_Subset_list, anchor.features = features)

#########
combined1 <- IntegrateData(anchorset = anchors)
DefaultAssay(tcell_combined1) <- "integrated"
combined1 <- ScaleData(combined1, verbose = FALSE)
combined1 <- RunPCA(combined1, npcs = 30, verbose = FALSE)
combined1 <- RunUMAP(combined1, reduction = "pca", dims = 1:10)
combined1 <- FindNeighbors(combined1, reduction = "pca", dims = 1:10)
combined1 <- FindClusters(combined1, resolution = c(0.2, 0.3,0.4,0.5, 0.7))

########
sel.clust = "integrated_snn_res.0.3"
combined1  <- SetIdent(combined1 , value = sel.clust)
table(combined1 @active.ident)

###### DE #####
#Compute differentiall expression
markers_genes <- FindAllMarkers(
    combined1 ,
    log2FC.threshold = 0.2,
    test.use = "wilcox",
    min.pct = 0.1,
    min.diff.pct = 0.2,
    only.pos = TRUE,
    max.cells.per.ident = 50,
    assay = "RNA"
)

OUTPUT

Calculating cluster 0
Calculating cluster 1
Calculating cluster 2
Calculating cluster 3
Calculating cluster 4
Calculating cluster 5
Calculating cluster 6
Calculating cluster 7
Warning: No DE genes identifiedWarning: The following tests were not performed: Warning: When testing 0 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 1 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 2 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 3 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 4 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 5 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 6 versus all:
    data layers are not joined. Please run JoinLayersWarning: When testing 7 versus all:
    data layers are not joined. Please run JoinLayers