Customize bullet points in vertical timeline

I rewrite the solution in LaTeX3, which supports stride values other than 2.

Update

documentclass{article}
usepackage[dvipsnames]{xcolor}
usepackage{etoolbox}
usepackage{xtab}
usepackage{array}
usepackage{fontawesome5}
usepackage{graphicx}
usepackage{tikz}
usepackage{adjustbox}
usepackage{expl3}

definecolor{accentcolor}{RGB}{ 250, 150, 10 }
definecolor{accentcolortwo}{RGB}{ 50, 150, 10 }

ExplSyntaxOn

int_new:N g_bullet_index_int
dim_new:N g_bullet_rule_width_dim
% vertical rule width
dim_gset:Nn g_bullet_rule_width_dim {1pt}

% bullet stride
int_new:N g_bullet_stride_int

% get the width of the arrow
dim_new:N g_arrow_width_dim
hcoffin_set:Nn l_tmpa_coffin {faArrowCircleLeft}
dim_gset:Nn g_arrow_width_dim {coffin_wd:N l_tmpa_coffin}

% the value is used to compensate for bigger circle
% at the bottom
fp_new:N g_arrow_width_factor_fp
fp_gset:Nn g_arrow_width_factor_fp {0.90}

% compute new arrow width for background circle
dim_new:N g__arrow_width_dim
dim_gset:Nn g__arrow_width_dim {fp_use:Ng_arrow_width_factor_fp g_arrow_width_dim}


% compute lap value
dim_new:N g_bullet_lap_dim
dim_gset:Nn g_bullet_lap_dim {
  0.5g_bullet_rule_width_dim + 0.5g_arrow_width_dim
}

newcommand*{resetbullet}{
  int_gset:Nn g_bullet_index_int {0}
}

newcommand*{setbulletstride}[1]{
  int_gset:Nn g_bullet_stride_int {#1}
}

newcommand{dobullet}{
  % draw verticle rule
  color{accentcolor!80}vrule width g_bullet_rule_width_dim
  % draw bullet at correct position
  int_compare:nNnT { int_mod:nn {g_bullet_index_int} {g_bullet_stride_int} } = {0} {
    color{accentcolor}
    adjustbox{left=0cm,
      lap=-g_bullet_lap_dim}{
      tikz{
        node[circle, fill=accentcolor!80,
              minimum~width=g_arrow_width_dim,
              inner~sep=0pt,
              outer~sep=0pt]
              {};
        node[circle,fill=green,
              % manually tune the width of arrow so that their size fit
              minimum~width=g__arrow_width_dim,
              inner~sep=0pt, 
              outer~sep=0pt] 
              {};
        node[inner~sep=0pt,
              outer~sep=0pt]
              {faArrowCircleLeft};
       }
     }
  }
  hskip-0.0pt hspace{labelsep}
  % increment counter
  int_gincr:N g_bullet_index_int
}

ExplSyntaxOff

newcolumntype{F}{<{hskip 0pt} !{dobullet} >{raggedrightarraybackslash}p{3cm}}


begin{document}


renewcommandarraystretch{1.2}

% set stride to 2
setbulletstride{2}
% reset bullet counter before new tabular
resetbullet

begin{tabular}{lF}
     1 & Test
    2 & Test 
    3 & Test
end{tabular}

vspace{1em}

% set stride to 3
setbulletstride{3}
% reset bullet counter before new tabular
resetbullet

begin{tabular}{lF}
     1 & Test
    2 & Test 
    3 & Test 
    4 & Test
end{tabular}

end{document}