diff --git a/.Rprofile b/.Rprofile
deleted file mode 100644
index 0f860de..0000000
--- a/.Rprofile
+++ /dev/null
@@ -1,2 +0,0 @@
-library(roxygen2)
-library(devtools)
diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index f36e31f..e2f46c8 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -8,27 +8,16 @@ name: R-CMD-check
 
 jobs:
   R-CMD-check:
-    runs-on: ${{ matrix.config.os }}
-    name: ${{ matrix.config.os }} (R ${{ matrix.config.r }})
-
-    strategy:
-      fail-fast: false
-      matrix:
-        config:
-          - {os: macos-latest,   r: 'release'}
-          - {os: windows-latest, r: 'release'}
-          - {os: ubuntu-latest,  r: 'release'}
-          - {os: ubuntu-latest,  r: 'devel'}
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
       - uses: actions/checkout@v4
 
-      - uses: r-lib/actions/setup-pandoc@v2
-
       - uses: r-lib/actions/setup-r@v2
         with:
-          r-version: ${{ matrix.config.r }}
-          use-public-rspm: true
+          r-version: 'release'
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
@@ -37,4 +26,5 @@ jobs:
 
       - uses: r-lib/actions/check-r-package@v2
         with:
+          args: 'c("--no-manual", "--as-cran")'
           upload-snapshots: true
diff --git a/.gitignore b/.gitignore
index ee875fc..b4aaf6d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,7 @@ tests/testthat/_snaps/
 # devtools / roxygen
 /doc/
 /Meta/
+
+# local R session config (machine-specific)
+.Rprofile
+.Renviron
diff --git a/DESCRIPTION b/DESCRIPTION
index 45826ab..ed8a611 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -19,5 +19,3 @@ Imports:
     parallel
 Suggests:
     testthat (>= 3.0.0)
-Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.1.2
diff --git a/tests/testthat/test-optim_SQGDE.R b/tests/testthat/test-optim_SQGDE.R
index a2dce99..a7228b8 100644
--- a/tests/testthat/test-optim_SQGDE.R
+++ b/tests/testthat/test-optim_SQGDE.R
@@ -5,7 +5,8 @@ library(graDiEnt)
 test_that("MLE factorizable MVN recovers sample means", {
   set.seed(42)
   true_mu <- c(-1, 1, 0, 2)
-  data <- matrix(rnorm(500 * 4, mean = true_mu, sd = 1), nrow = 500, ncol = 4)
+  data <- matrix(rnorm(500 * 4, mean = true_mu, sd = 1),
+                 nrow = 500, ncol = 4 ,byrow = TRUE)
   analytic_mu <- colMeans(data)
 
   neg_log_lik <- function(x, data) {
@@ -44,7 +45,7 @@ test_that("MLE factorizable MVN recovers sample means", {
 
 test_that("univariate objective recovers sample mean", {
   set.seed(42)
-  obs <- rnorm(300, mean = 2.5, sd = 1)
+  obs <- rnorm(300, mean = 4, sd = 1)
   analytic_mu <- mean(obs)
 
   neg_log_lik_1d <- function(x, obs) {
@@ -59,9 +60,9 @@ test_that("univariate objective recovers sample mean", {
         n_params    = 1,
         n_iter      = 500,
         n_particles = 6,
-        n_diff      = 1,
+        n_diff      = 2,
         init_center = 0,
-        init_sd     = 2
+        init_sd     = 1
       ),
       obs = obs
     )
@@ -155,8 +156,9 @@ test_that("PSOCK parallel execution returns valid solution", {
   skip_on_cran()
 
   set.seed(42)
-  true_mu <- c(-1, 1, 0, 2)
-  data_par <- matrix(rnorm(500 * 4, mean = true_mu, sd = 1), nrow = 500, ncol = 4)
+  true_mu <- c(-1, 8, 0, 2)
+  data_par <- matrix(rnorm(500 * 4, mean = true_mu, sd = 1),
+                         nrow = 500, ncol = 4 ,byrow = TRUE)
   analytic_mu <- colMeans(data_par)
 
   neg_log_lik <- function(x, data_par) {
@@ -201,7 +203,8 @@ test_that("FORK parallel execution returns valid solution", {
 
   set.seed(42)
   true_mu <- c(-1, 1, 0, 2)
-  data_par <- matrix(rnorm(500 * 4, mean = true_mu, sd = 1), nrow = 500, ncol = 4)
+  data_par <-  matrix(rnorm(500 * 4, mean = true_mu, sd = 1),
+                         nrow = 500, ncol = 4 ,byrow = TRUE)
   analytic_mu <- colMeans(data_par)
 
   neg_log_lik <- function(x, data_par) {